You Won't Believe the Difference: 9, 6.5 & 5 Bar OPV Mod with Flow Rates for Gaggia Classic Pro

[@TomsCoffeeCorner]

📚 Read the blog post here: tomscoffeecorner.com/gaggia-classic-pro-9-bar-mod/ Subscribe for more coffee reviews & tips! www.youtube.com/@TomsCoffeeCorner?sub_confirmation=1 ►The Gaggia Classic Pro: geni.us/GaggiaClassic (worldwide Amazon link) ►Eureka Specialita Grinder: geni.us/EurekaSpecialita (worldwide Amazon link) ►Bottomless Portafilter: geni.us/GaggiaBottomlessPF (worldwide Amazon link) ►Precision Tamper: geni.us/Motta58_4 (worldwide Amazon link) AFFILIATE DISCLOSURE: Some of the links used in the description will direct you to Amazon, as an Amazon Associate I earn from qualifying purchases at no additional cost to you.. Affiliate commissions help fund videos like this one.

[@chriskvikstad4980]

Hi Tom, I know this is an older video but the topic is very current, especially for those of us with Gaggia Classic Pros and other smaller, vibratory pump espresso machines that are shipped from the factory calibrated to higher pump pressures. I have been feeling disappointed with my spring mod for my Gaggia Classic Pro. I installed the 9 bar spring and it just hasn't made much of a difference for me, so I started really deep diving into what is going on. I found this interesting video from the Espresso TV channel regarding pump pressure differences. In the video, the host visits the Bezzera factory in Italy and he talks about pressure with Luca Bezzera (the grandson of the man who invented the espresso machine). Luca Bezzera says that with small espresso machines using these tiny vibratory pumps, they have to be calibrated using higher pressure at the pump in order to get the proper flow rates and pressure at the group head during extraction. There is significant pressure loss between the pump and group head during the actual extraction process. He said they need to have 12+ bars of pressure at the pump because the pumps are so tiny. In contrast, large commercial machines and prosumer machines using rotary pumps are calibrated at 9 bars of pressure because the pumps are so much larger and more powerful. He's a native Italian speaker, so he's having some language barriers at times going between Italian to English, but he gets the point across. The host of Espresso TV is a German hydrodynamic engineer who used to design large pumping systems at water facilities. He understands the fluid mechanics involved and his English is really proficient, so he does a good job of trying to explain the basic physics in the comments section. I believe Marc at Whole Latte Love has recreated some of these test experiments. I can't find his video at the moment. To accurately measure pressure loss between the pump and group head during an extraction, there needs to be a device attached to the portafilter that allows water to flow out at the proper extraction flow rate to simulate an actual extraction while the pressure is simultaneously being monitored at the portafilter. If you do your test first, to measure the pump pressure, then you can conduct this second experiment to calculate the pressure loss in your machine during extraction. Then you know with certainty what pressure you are really extracting with. Marc said there is so much pressure loss with the Gaggia Classic Pro that you are not extracting anywhere near 12 bars of pressure with the standard OPV spring. Here is the Espresso TV Bezzera video. I thought you might find it interesting in case you haven't already seen it. kzbin.info/www/bejne/e2XcZWB7Z8Z_abcsi=0JljcV2IEwJsZfth

[@phatmilkers2074]

Thanks A LOT man

[@iggyman83]

Okay but you're not adjusting the pump pressure - you're adjusting the over pressure valve limit. The pump is doing it's thing at whatever bar, and the opv receives the water at that raw pressure and is simply rerouting some water back to the tank to keep the pressure at the puck to what you choose via the adjustment screw/spring. No offence to WLL but they are a retailer and the last thing they want is people thinking a popular product doesn't work out of the box, or feeling they need to go to the extent to modify it. They're thinking through the lens of someone having to sell the machine, not use the machine. The reality is most well engineered espresso machines now have externally adjustable OPVs for this reason. Add a manometer and it's easier to adjust.

[@lostboy8814]

Hi Tom,I am another convert thanks to your excellent advice.The 9 bar spring mod which I successfully undertook thanks to your video,the difference is night and day,it is way better,my shot has a far better crema,and the shot now has that wonderful silky appearance that I have come to appreciate in great expresso.I am absolutely delighted in the difference and the results,so thank you so much for dialling me in to near perfection,kudos to you Sir.

[@TomsCoffeeCorner]

Thanks very much for your comment, and for sharing! Tom

[@SpartacusDog]

Thank you, Tom! Of all the hundreds+ coffee videos on KZbin, on hundreds+ topics, yours are invariably the very best. Your videos are better thought through, they are the clearest, and your explanations are the most informative. You've greatly elevated my coffee brewing IQ and greatly informed my coffee making decisions. All I can add is thanks again.

[@TomsCoffeeCorner]

Wow, thank you so much for such kind words, I really appreciate it!

[@BobMacNeal]

I appreciate seeing the comparison of all the Shades of Coffee spring mods for the GCP. Based on your previous instructional video, I installed the 9 bar spring from Shades. I also do about a 5 second pre-infusion step for my all of my shots (aiming for 1:2 recipe). I've been very pleased with the results. Thanks Tom.

[@TomsCoffeeCorner]

Hey Bob, thanks for the feedback! I also like to do a short pre-infusion (steam valve cracked), and that seems to make the shots even smoother. Glad you like the mod! Cheers ☕️

[@DrHankVenture]

Hey, I came back to tell you that this was the MOST HELPFUL video for these mods. I put the 5.5 bar in my machine, and I cannot believe how good my shots have become. They're absolutely incredible. Thank you so much for for this!

[@TomsCoffeeCorner]

Glad I could help! So happy to hear you're loving the shots you're getting!

[@tomaszdrgas8811]

I like the wideo but result was what i expected (vs unbelievable title) even though i have heard first time about any spring being involved.. still very helpfull informations

[@Psychoh90]

Appreciate the content and the flow comparison :) My only issue with the taste comparison is that the GCP users need to be careful of temperature surfing. Sure the flow rate had impacted the flavour of the coffee, but at the same time it could be the not perfect temperature surfing (not showed in this video). A part from that, flow comparison is great and I switched just last week from the standard to the 9Bar

[@TomsCoffeeCorner]

Great point, Leonida! Aside from the temperature surfing, and you are right there, I would also have to redial the grinder for each brew pressure. But I thought the video would be more visually interesting to first exhibit the flow rate differences. Thanks for commenting! Tom

[@SunriseLAW]

After significant experimentation, imo the best results from my GCP come from the original spring (13 bar?) and the Dimmer Mod. That allows me to ramp up the pressure and taper it off. I was watching a vid (I think it was the "Decent" machine) and it automatically ramped it up/down such that it peaked at 17 bar (?). That gave me the idea to try it on the GCP and put the original spring back in, and I think the results are better.

[@TomsCoffeeCorner]

Thanks for posting your experience! Tom

[@phyx1s]

You don't need to order the new spring. Just use the standard spring (and make it shorter) and loosen the brass screw (with the silicone hose). This loosens the spring and lowers the pressure. You can use some gas-sealing tape on the thread to prevent any leakage. There is no water pressure in the silicone hose. But you will need a pressure meter.

[@TomsCoffeeCorner]

Just be aware that this might not be that easy to do. I tried a similar experiment on the Delonghi, and the pressure did not seem to be linear based on the spring shortening.

[@phyx1s]

@@TomsCoffeeCorner That true. You need to have the pressure measurement to adjust accurately, not on length measurement. The spring can be adjusted roughly. The fine tuning by turning in or out (a little bit) the brass spring holder nut. I managed to go to 9 bar with the original spring without cutting it. But better is to shorten it a bit, it will fit better that way.

[@j.t.1215]

Ha ha!! I am learning well! I first thought, why on earth would we use that stock basket when Tom recommends the IMS (for my Delonghi)? Then, you answered my question. Glad that this video came up today.

[@TomsCoffeeCorner]

Well, the stock baskets are ok, but not great. Check out this Lelit OEM basket vs IMS: kzbin.info/www/bejne/pqDKqa2AgtSIg9U

[@FernandoCastro-ey1mz]

clear and great explanation, thanks!

[@enesvekshari4395]

Nice one Tom. I have only tasted 12bar and 9bar ones, I think the lower the pressure more acidic it gets and its definetly not for my taste. Shame the spring mod doesnt work on the dedica though :/

[@TomsCoffeeCorner]

Totally agree, Enes! I prefer the 9 bar, of all of these springs. But it is an interesting test for sure. I think I could remove a little acidity by adjusting the grind settings, but I wanted to notice a difference in flow rate, based on pressure.

[@MereCashmere]

The lower the pressure, the quicker the shot needs to be. Search “turbo shots” and you’ll understand. You can’t use the same grind/ brew time for a 9 on a 6 bar spring; for the 6, grind more coarse and speed the shot time.

[@damonm3]

So I ordered a 3 spring combo off of ebay. Shipped 10 days ago and for some reason isn’t here yet. Was hoping to have it now! I look forward to playing around with times/ratios with the 9 and 6.5. I almost always do a 2:1 ratio and find the closer to 30 seconds the better. I’m using the bst 18g basket and a screen and grind 18-21g of coffee depending on the roast. I like lighter roasts most and they’re more dense so 20-21 g and fit a screen in too. I like strong too obviously 🏆

[@TomsCoffeeCorner]

Hey Damon, I am not sure where you ordered from, but for me it took a few weeks, due to customs. Hope you have fun experimenting with the springs! Tom

[@damonm3]

@@TomsCoffeeCorner ah, maybe that’s it. From china.. thanks man! Keep experimenting too. It’s part of the fun for sure☕️☕️

[@TomsCoffeeCorner]

Oh yeah, from China it will take maybe 6 weeks.

[@wakeawaken430]

Nice video Tom Experimenting with my rancilio Epoca that comes from the factory with 12.5 bar, I found out that everything under 11 bar static pressure was unacceptable Coffee flat, no taste, no acidity, very bad aftertaste, all coffees same bad taste Only a very dark roast was acceptable but nothing special Seems that the pressure at flow is much lower, maybe 4 bar less, at MY machine, but I don't have a scase to test it What I saw is that as the pressure drops, the acidity drops too, but the good acidity, the acidity we want That's why my machine is now set at 13 bars static pressure Taste comes first, I really don't care if there is some channeling

[@TomsCoffeeCorner]

Thanks for your feedback! For me, mouth feel and a balanced shot are the most important (not too sour or bitter), and 9 bars seems to provide that the best for my palate. But, since everyone's palate is different, I can imagine there are varying results. Cheers!

[@wakeawaken430]

@@TomsCoffeeCorner off course coffee is a personal subjective thing As I said, after a lot of trial and error and opinions of all over the world, I came out that for vibe pump machines the optimal set is 10.5-12 bar(static), for rotary pump 8-9(static) and with levers you can drop to 6 bar And off course is based to the level of roast When the first lever came out, they used to drink very dark roasts But with the right method you can have very good light roast extractions, that's why bezzera put a vibe at 11 bar for preinfussion at strega, and then the spring takes control

[@nonyago]

@@wakeawaken430 very good point. I went from a vibration to a rotary pump and had to dial down the pressure. I still don’t get the same flavor profile as with my vibration pump. 🤔

[@jacobbellman9832]

This is great! I’ve been thinking a lot about this since I swapped out for the 9 bar spring and one thing I’m curious about is if you tried to dial in much for each spring? For instance, I would assume for the 12 bar spring you could reduce grind size a bit to get in the 20-30 second shot range. Similarly for the 6 or 6.5 bar spring if you go coarser I would think you could aim for the turbo shot range (10 - 20 seconds) to get a similar extraction. Thanks for putting in the work for this, I would love to try it but I’m too lazy!

[@TomsCoffeeCorner]

Hey Jacob, sure I can do this. I just need 1 kg of some good beans, and some time. ;) I plan todo a follow up video in the future, and then I can show how the grind adjustment changes based on the OPV pressure. Cheers!

[@jacobbellman9832]

@@TomsCoffeeCorner cool, can’t wait to see the results!

[@HannesNitzsche]

Thank you for putting this video together. I would be interested in a follow-up where all the shots have been properly dialled in for each pressure setting. Over the last 6 months I’ve also experimented with all four springs and personally I love the 6.5 bar OPV. I only drink long blacks so steam pressure is not an issue but I want the best flavour. The 6.5 bar spring affords me the most consistency and best flavour in my opinion and I found the 5 bar spring lacking body. Contrary to other comments here I actually had to grind slightly finer as I went from 9 to 6.5 bar, and finer again from 6.5 to 5 bar. I’d be interested in a deep dive comparison of all the springs and to see if you would recommend a specific brew ratio for the lower pressure springs. Cheers from Australia!

[@TomsCoffeeCorner]

Thank you for the idea, Hannes. I plan to do this in the future. It is interesting that you had to grind finer at lower pressures. What kind of grinder are you using? What brew ratio do you like for lower pressure springs? Cheers from Germany! ☕️

[@HannesNitzsche]

@@TomsCoffeeCorner As far as I understand, when the pressure drops the flow rate will increase leading to faster shots. Hence the finer grind size. I spoke to several others on reddit who had the same experience. I’m using a 1ZPresso K-Plus hand grinder. The grind adjustments are rather large at 22microns per step on the K-Plus, thus I only had to grind one step finer when I went from 9 bar to 6.5 bar. Personally I’m a fan of the classic 1:2 ratio. But to be honest, because I like the flavour at that particular ratio in my long blacks, I tend to just stick with it and not experiment with other ratios that much, which I probably should. Maybe you can sway me with your upcoming video, which I’ll look forward to. Cheers ☕️

[@pedrotrberaldo]

Hi Tom! Question from someone starting their coffee journey: Considering that the extraction from the 12bar had bad taste, do you think it could be dialed in (using other variables) to taste better, or would you say that you had exhausted other variables and what was missing was the pressure difference, really? Or rather, you wanted to use the pressure difference to really show the difference it makes in the extraction and flow, plain and simple? Thanks for the great video!

[@Moreno_Cubanito]

depends on the roast though Light roast you need more of an extraction to remove the sourness because it needs more time to extract the flavor and more heat and for dark roast over extraction will give a bitter taste and you may want to lower the heat. I have a flow control to play with different bars of pressure with different roast types. So its more to it than bars of pressure. Roast type and temperature of water is just as important.

[@jessnguyenthi7266]

May I ask, so light roast, do we need higher bar or lower bar?

[@Moreno_Cubanito]

@@jessnguyenthi7266 I have a newer machine. And I can control my bars a lot better now. I tend to like less bars of pressure to get more flavor. Play around 6 to 8 bars. For me it seems to have slightly more sweetness to the cup with lower bars. But you are saturating longer with a lower bar.

[@marcing4287]

I use internal in-line pressure gauge. I have adjustable OPV. To adjust a pressure, if I do not have a pressure gauge on the portafilter, how can I start adjusting ? Can blank basket be used ?

[@Al4stars]

Great videos and tons of necessary info Tom, i have the same Gaggia machine and replaced the spring to a 9 bar however my machine is still brewing to fast on about 15 sec and i get no crema at all, i also replaced the portafilter to a bottomless, i am using Lavazza Crema A Aroma which im getting a descent crema on an fully automated Seaco intellia machine, do you have any recommendations/suggestions ? struggling here lol thank you

[@TomsCoffeeCorner]

Hello there! Yes, your beans are probably too old - or in other words roasted too long ago. These videos may help: How to extract the perfect espresso: kzbin.info/www/bejne/ppqyZ5ZsbpqCppo How to Get Crema: kzbin.info/www/bejne/ZmGxhHpvaZpsl5o Why Supermarket Coffee Beans are RUINING your Espresso! kzbin.info/www/bejne/a3PKfn6nqp2ZgKs

[@Al4stars]

@@TomsCoffeeCorner thank you 🙏🏻

[@TheWillHargrave]

I have seen this mod in so many places and never fully understood it. You released this video like 2 days later and it was everything I wanted to know about the OPV spring mod. Thank you Tom! Thank you for being more thorough and 'scientific' than a lot of other channels. Quick note on your video production. Your voiceover audio sound amazing! But your talking head/live audio could use a little upgrading. And the video is a little long with a lot of transitions. If you tightened up your pacing and made the transitions a little more unique/quick to add to your video style I think you'll really find some good success. I love your "quick time lapse" style while working on the machine. Very helpful and visually interesting. Overall Great job man! You need to start a Patreon and start building a following. You're well on your way to full fleged KZbin sidegig.

[@TomsCoffeeCorner]

Hey Will! Thanks so much for your thoughtful comment! I do appreciate your feedback on the video production, as I do want to improve over time. Regarding audio, most of it was recorded with a lapel mic. There are only a couple of voiceovers, at 2:10, 7:22 and 8:10 where I was using a Blue Yeti mic in my office (because I had forgotten to narrate those in real time). Are those the times where you think the audio sounded better? I went back over the video, and the audio of the lapel has some reverberation, if that's what you mean. The transitions help me organize the video in the timeline, but I could omit them next time if they disrupt the flow of the video. Anyone else have thoughts on this? Again, thanks very much for taking the time to watch the video, and write down your thoughts. 👍 Cheers! ☕️ Tom

[@Clynikal]

I watch a crazy amount of these types of videos and I think the layout was spot on. Well done.

[@TomsCoffeeCorner]

@@Clynikal Thanks, Clynikal! 👍

[@dirkl216]

I found this very useful. One it kept me from doing it myself 😂. seriously, I have the same springs from mrshades also and decided on the 9 bar one. i also use pre-infusion alternately as I go through my bag of beans. For the GCP there are so many variables to explore. I will be looking at the dimmer mod next using Lance's suggestions.

[@TomsCoffeeCorner]

I agree with you there, Dirk. There is so much to experiment with, and so many available mods. Should be good fodder for future videos. 👍

[@threehanded8853]

Use the Sam Burchard Dimmer that Lance mentions, kzbin.info/www/bejne/a6Ooc6CZhZaNi9E

[@Gk2003m]

Dimmer mod (along with adjusting to 9 bar) has made all the difference on my Saeco. I pre-infuse; I have 28 seconds from first drop to completed extraction, and it is delicious with a velvety mouth feel

[@DelReiRock]

Wow! Please make a video how to create this volcano extraction… 😮

[@DimHim7473]

So,if you have a single origin coffee that needs 32 sec extraction for 2 to 2,5 ratio,what you do? You stay with this recipe and install the 6,5 bar spring or you change up the grams of recipe and go for 9 bar spring? 😊

[@charlesbelliard8278]

I have the solis barista perfeta plus and extracting from factory at +12 bars. Do you recommend doing the 9bara MOD that seems a bit tricky?

[@TheOwlol]

Dont you need to adjust the grind when changing spring?

[@TomsCoffeeCorner]

I think that is a good idea, once you choose a spring to go with. If I would choose the 5 bar spring for example, I'd coarsen the grind a bit. It runs a little long otherwise.

[@jmsaffroy]

@@TomsCoffeeCorner You certainly want to adjust grind size for taste, but as you indeed have to grind coarser, you should see even less channeling, and that's another definitive improvement in taste.

[@areyouarobotz]

Coffee machine companies are missing out on selling this feature like it needs to be higher up so everyone can see the bottom like you show in the video. I would just make coffee all day to see that trip thing

[@TomsCoffeeCorner]

💯 I totally agree. It's so fun to watch the extraction. 😉

[@Horologiist]

This one is really helpful to me. It shows the whole story of pressure in making espresso. You re going to fix it via the opv valve, others heading for pressure profiling using way more expensive equipment. But at the end all of us trying to trick the pump in some ways. As a Rancilio Sylvia user im asking myself if it wouldnt a be smart move to get myself a lever machine and get rid of the pump?! What do You think? Thanks for this vid!

[@TomsCoffeeCorner]

Hello Ma Jo! Yes, a lever machine would provide the ability to spontaneously adjust pressure on the fly. I bet that would be fun to use. I am hoping to test a La Pavoni soon. What kind of lever were you thinking?

[@Horologiist]

@@TomsCoffeeCorner Hey Tom, thx for your reply. Im not at a point for decision making yet. I just came across this pressure profiling hype while im trying to figure out pros and cons about PID for my Sylvia. Because i always try to understand whats happening whitin a process on a way to a favored result. Then i watched your vid and got to the idea a spring lever machine might be the most easiest way to further improve the really good results my Sylvia is doing. So, i think your re right, testing some different systems is next. Have fun..

[@TomsCoffeeCorner]

@@Horologiist For me, part of the fun of espresso is the preparation. I think that using a lever machine would be fun. More fun than a conventional machine. And it is even better that you can dynamically adjust the pressure. Cheers!

[@mullaccount4015]

Thank you Tom for the informative video modding the gaggia. I found it very helpfull to get the measurements in the video description - thanks for that as well. Did you measure the 9bar spring too? Or is there a typo in the description - 9bar instead of 12bar? I would like to order some springs at another manufacturer ;)

[@TomsCoffeeCorner]

Servus! Here are the values. Where do you plan on buying them? Please do share, as I had to pay quite a bit of import duties to get these from the UK to Mainland Europe. 12 bar spring: 23.6mm long and wire strength of 0.6mm. 9 bar spring: 19.5mm long and wire strength of 0.6mm. 6.5 bar spring: 23.9mm long and wire strength of 0.5mm. 5 bar spring: 20.1mm long and wire strength of 0.5mm

[@thesulsaja]

great video, good pronunciation. easy to listen.

[@КонстантинБыстряков-с7з]

Tom, thanks for video & knowledge!!! So, what was Flow Rate when you install PRESSURISED basket ?

[@TomsCoffeeCorner]

Hey there! Oh, that’s a good question. I didn’t test that. I would have had to make the grind much different (coarser) in order to use the pressurized ones. Cheers! Tom

[@zimzum67]

I love yr videos Tom!

[@robvercouteren]

Looking good, but im curious about the different cafestol levels compared to filtered coffee.

[@TomsCoffeeCorner]

Hmm, good question. Wouldn't know how to measure such a thing.

[@tgeorgom]

Thank you for the video and instructions. I have an old gran gaggia prestige. Do you think that this hack also applies to my machine?

[@TomsCoffeeCorner]

Hi there! I have never opened one of those, so I don't know. They have used numerous OPV designs over the years...

[@jolynnelockley9013]

A friend gave me his Isomac Venus. There are some issues. The coffee (Peet's fresh, find grind) flows too quickly and is a weak. There is no crema. Could this be a spring issue? Thank you.

[@MrAngchristopher]

Hi Tom, nice comparison you made. Just a quick question, when you use the pressure portafilter , do you still put the basket in the portafilter, thanks

[@TomsCoffeeCorner]

Do you mean when I use the press rice basket? That can only be used in conjunction with a normal portafilter. Cheers! Tom

[@SandySadow]

Thanks Tom for excellent video. I am trying to install a 9 bar spring in my new Gaggia Classic Pro, but ran into a problem. Top cover off, pulled the tube to OBV out of bottom of machine so that it is free to turn. Problem: I am unable to unscrew the brass fitting that holds the spring (using a 10mm wrench). I'm afraid that if I push any harder I will break something. Has anyone experienced this problem and have a solution?

[@TomsCoffeeCorner]

I am not sure about that. I changed my spring while the machine was still new, so unscrewing the brass fitting was pretty easy. It might get caked on over time, especially with limescale and so on. Perhaps someone can post a good hint here?

[@SandySadow]

@@TomsCoffeeCorner The machine is brand new, so no limescale. A hint from someone who had the same experience would be wonderful.

[@tskolits]

Great video! Thanks!

[@vnamahi4056]

Wow i love this crema

[@lanbai-yr7lz]

Very helpful!

[@damonm3]

Just dropped in a 6.5.. hood it holds true to taste a little more acidic. But I’d imagine you could get any range of sweet/bitter/acidic with grind and water temp..

[@TomsCoffeeCorner]

Which spring pressure do you like best of the 3?

[@damonm3]

Well, 9 was great, but 6.5 seems ever better. It could just be different tho. Confirmation bias is always at play.. only made 2 lattes at 6.5…Making another after dinner in 20 or so.. I’m set on mixing a few blends that I really like. So if they’re blends I’m now mixing 4 or 5 different beans? Haha… both local roasters near Fort Collins and boulder. Jackie’s Java (mostly make flavored yuck but their dads blend is insanely smooth medium roast blend) honestly haven’t tried any other beans from them as they’re flavored. And OZO Isabelle medium/light blend. Tried dozens of beans ranging from awful to good. But only a few I classify as great. O, there’s one more I forgot about. intelligentsia house blend, almost didn’t try the brand as the name is stupid imo.. think they’re out of Chicago.. amazing light roast. But I also mix this with one of the other two most of the time as I prefer it mixed. Have a top three you rec? O, and I use a sette 270 and an18/36 or 38 out. Preheat for a while, and make sure it’s up to temp prior to shot by activating brew till light goes off. Then steam switch for 3-5 sec to make it even hotter. I’ve tried 10 sec and it burns at that point. The lighter the roast the more heat. So maybe I’ll try no steam button for medium roast just to see… and 5-6 sec for LR. Any recommendations or adjustments? O, also steam on, purge, wait till 25 sec, purge for 5 sec, wait till 45, purge then steam. 75/25 WM/HH 200ml mix.. anyway, tmi… thanks for the videos!! Edit: o and of course I do the rest of stuff to get the optimal shot like pre-infusion, a paper puck filter on top to keep internal soot down, bottomless 18g precision filter, also have a curved BOB 18g. I’ll have to try it again. Not too impressed by it tho. Might just be marketing gimmick.. and I’m embarrassed to admit I didn’t clean backflow for a long long time. And now do it weekly. So not drinking rancid coffee is a huge step up. Made such a huge difference. I was getting very inconsistent shots depending on how much yucky old grinds were contaminating latte. Still haven’t descaled, had for 1.5yrs. Hope it’s not a humongous deal 😂.. and filtered BST water, ok, I’m now done with commenting haha..

[@許伯任-k9z]

Why your extraction seen to tilt a side? thanks to the amazing insight sharing.

[@TomsCoffeeCorner]

Hey there! It always seems to do that. It is more pronounced with the 12 bar spring though. Cheers!

[@phillipto09]

maybe check for how even the flow of water is out of the shower screen as well as seeing if the machine is level

[@maycatyuiop]

Late to the party but i wonder if this is due to the machine not being perfectly level

[@playbackamusicloversjourne8620]

excellent video thanks! Subscribed.

[@TomsCoffeeCorner]

Thanks for the sub and for watching!

[@MrAngchristopher]

Hi Tom, nice video you made, save me time to test. I installed the 9 bar spring, but for some reason mine was reading 10.5 to 11 bar. BTW I’m also using the same pressure gauge your using. I removed and try to install still got the same pressure. Do you think the spring had issue? Also I like the way you did, not removing not tube, I think that’s one of the annoying part. Thanks

[@TomsCoffeeCorner]

Hi there! Which kit did you use? From Mr. Shades, or somewhere else? What pressure does your original spring read?

[@pedrolucca3861]

hello, Are the baristagadgets springs calibrated correctly? have you tried them? do you recommend them? since you do the test with those from Shades of Coffee. thank you

[@TomsCoffeeCorner]

I've been recommending them to US and Canada customers, to save shipping time and postage. People have been very satisfied with them.

[@guitarplaya47560]

Great video outlining some of the differences between the 4 springs - does a large cone as seen on the 12 & 9 bar spring mean anything in particular or this is a natural occurrence? I currently have a 9 bar spring in my unit and depending on the beans, I see larger or smaller cones

[@TomsCoffeeCorner]

Hey Brandon, I notice a larger cone at higher pressures, and also with blends that have more robusta.

[@mtheo23]

really want to try the opv spring but man the shipping fee to south east asia is crazy expensive 😂 $60 shipping for a $10 spring isnt worth it

[@_allcap]

Thank you for the video but It would have been better if you did the 12bar with the pressurized filter

[@TomsCoffeeCorner]

Hey there, I have a video of the 12 bar with pressurized filter here: kzbin.info/www/bejne/ppW2ZpSdr6Z2qJY

[@jmsaffroy]

Last year I got an older (used) Gaggia Classic, with the adjustable OPV. The previous owner had left the OPV at factory setting, so I knew had to reduce the pressure. But I didn't want to spend the extra money for a pressure gauge (not so early in my espresso journey), so I measured the OPV output flow (with a blind filter) and adjusted until the flow suggested that the pump was operating closer to 9 bars (there is a table for Ulka EP5 pumps linking pressure to flow). Then I pulled shots for months, with increased success over time as I refined my technique (puck prep, better grinder), though problems were not rare. Eventually I bought a pressure gauge (and a portafilter that could accomodate it, as mine could not). Turned out the pressure was actually 11 bars (so the original pressure might have been well over 12 bars, maybe 13 or 14!). I tuned the OPV again, this time to 9 bars really (on the gauge). Now my espressos taste better, in general "rounder", with less harshness, which I think is a sign of less channeling (I do have a bottomless PF, so I know to look for visible defects). Eventually I'll have to try lower pressures, but going down from 11 bars to 9 is already quite an improvement! To me, installing a PID and adjusting pressure are essential mods, so much so that I cannot recommend the Gaggia Classic without them (PID comes first though).

[@jmsaffroy]

Speaking of the PID mod, I recommend this video: kzbin.info/www/bejne/kHLXpKiJa6dprsk It gives instructions and pointers to parts that give you a PID for much cheaper (about 60€) than well-known pre-assembled kits. :)

[@TomsCoffeeCorner]

Hey Jean-Marc, thanks for your comment, and telling us of your espresso journey. So, how did you measure the OPV output flow with a blind disc? Did you catch essentially the overflow and measure that weight? I also find that the 9 bar pressure results in the smoothest shot, at least with the grind setting in this video. Going lower than that resulted in more bitter shots, but then again I hadn't adjusted the grind accordingly, so that could be something for a future video. I have not installed a PID yet. I am an engineer by trade, so it should for sure be doable, but I have not found the time yet, and also most of those mods look aesthetically kind of off putting. Cheers, Tom

[@TomsCoffeeCorner]

I have seen that video (it's a good one, for sure), and it is nice to have it mounted on the back, but I really would like to see the timer while the shot is pulling. Still waiting for a mod kit that looks nice, and can be mounted ergonomically. Then, I will do a video about the install. 😉

[@jmsaffroy]

@@TomsCoffeeCorner Note that the PID controller showed in the video above does not work as a timer, it shows temperature only. As for placement, I find it easy to read the temperature with the PID on any side of the machine, as while standing up I really see it from above... but your machine, your choice. ;)

[@jmsaffroy]

@@TomsCoffeeCorner I directed the water hose exiting the OPV to a container, put a blind filter, ran the pump for 30 seconds, and weighed the water. After my first tuning of the OPV, this gave me 160ml in 30s, so 320ml/min, which, according to the Ulka pump spec chart, means that the pressure is between 5 and 9 bars. As you can see, that wasn't so close to what I later read from the gauge (11 bars). Maybe the cheap gauge itself isn't that accurate? Maybe the method is flawed? Maybe my pump is outside specs? (It's 16 years old now!) Anyhow, this crude method got me started for cheap, so I can't say it's all bad. What really matters is knowing that reducing pressure is definitely useful.

[@justinodelvalle6142]

I just ordered the springs from Shades of Coffee for my brand new Gaggia Classic Pro. Which of them is the best for espressos? Thanks!

[@TomsCoffeeCorner]

Hi! I like the 9 bar spring the most for the Gaggia. Cheers!

[@justinodelvalle6142]

@@TomsCoffeeCorner Thanks Tom. What about a dimmer switch; which one should I buy?

[@optical76]

Can’t find the springs anywhere. Looks like they’re all sold out. Any ideas where to find a 9bar? Thanks!

[@TomsCoffeeCorner]

Hmm, you're right. I imagine maybe the sellers have sold out over the holidays, and will restock soon enough. Maybe just check back in a few days. Happy new year!

[@highfell1]

Hi Tom -quick question ; what WTD tool , do you use.

[@TomsCoffeeCorner]

Hey! I linked it to the top of the description for you. Cheers! Tom

[@naBy4ok]

Is there a way to do the same on my dedica? It is also interesting what pressure does it produce by default. Haven't you tested it with the manomether?

[@TomsCoffeeCorner]

Yes, I tested it. It does a max of 11 bar, with a blind disc. But during an extraction, I get 8-9 bar. I would not suggest altering the pressure, as the OPV was not meant to be manipulated.

[@anotherguy9000]

Oh no Tom, thanks but now I have a problem: after making the 9 bar spring mod in my Gaggia Baby it worked so well that I now realize that my Delonghi Magnífica ESAM3300 over extracts coffee and I want to do the same to it - is it possible? It looks like the ESAM uses the piston for pressure and not the pump am I right? I thought of using the dimmer mod but don’t think it will work :-( any help?

[@TomsCoffeeCorner]

Hi there! The ESAM is a super automatic machine, which is not capable of espresso. It only operates around 3 bar. Cheers!

[@Katerman007]

I have an older model, were I can change the pressure over srewing with an allan key. Or do I need a new spring?

[@TomsCoffeeCorner]

No, the older models sometimes came with an adjustable OPV, which was more ergonomic. It compresses the spring through turning the allen screw. No need to buy another spring.

[@iconindexsymbol]

What does changing the OPV spring do? I thought only the machine’s built-in water debit and grind size of the coffee affected the resulting pressure.

[@TomsCoffeeCorner]

Hello! The OPV does limit the maximum pressure that can be built up, before getting re-routed back into the water tank. For example, with the 5 bar spring, anything over 5 bar will exit the OPV before it makes it to the brew group.

[@iconindexsymbol]

@@TomsCoffeeCorner Ahhh, so you have to grind coarser once you've installed the 5 bar spring?

[@TomsCoffeeCorner]

@@iconindexsymbol Yup!

[@LorenzoNW]

I wonder how the flavor profiles will differ between the 8 and 6 bar spring version of the Odyssey Argo.

[@TomsCoffeeCorner]

Well, that looks like a beautiful machine. It’s on pre-order, isn’t it?

[@LorenzoNW]

@@TomsCoffeeCorner Right, it seems to offer a lot of features for the money. It appears they're just selling direct. I'm going to wait until it's been out for a while and thoroughly reviewed before deciding to buy one. That also means buying a new grinder (maybe a DF64) because I just own a Virtuoso for making coffee with my Clever.

[@TomsCoffeeCorner]

@@LorenzoNW What do you mean by Clever?

[@LorenzoNW]

@@TomsCoffeeCorner Clever Coffee Dripper

[@gilad_rubin]

What is the technical name of this "flowing lava" effect that we see on these tests, where the coffee pours down from the shower head... I'm seeing this effect on my Breville Bambino and never understood why and if it's something I should try to avoid.

[@TomsCoffeeCorner]

I call it the "cone" and it is larger with higher pressures, higher heat, fresher beans, and beans with more robusta.

[@diederikgeertzen9469]

It's because in the beginning, there are more particles extracted from the coffee, resulting in a thicker flow. Later on, there are less particles extracted, thus less thicker coffee coming out

[@nickTHHGTTG42]

Do the different springs change the strength of the steam coming out of the Steam wand?

[@TomsCoffeeCorner]

Hmm, not sure about that. The OPV regulates pressure while the pump is pumping. During steaming however, you are not pumping any liquid, but rather heating up the water in the boiler. So I cannot imagine the steam is affected. Anyone else notice any difference?

[@Nevermindthrbrewmethod]

Now all you need to do is lower the flow rate by an order of magnitude and you're rocking.

[@HG-fq9eg]

Did you use the same grind size for all of the pucks?

[@TomsCoffeeCorner]

Yes I did. I wanted to show the difference in the result of the extraction, based solely on the variable of pressure.

[@jfrodriguez23]

So much crema! What beans are you using?

[@TomsCoffeeCorner]

Hello Jose, these ones: ☕️ COFFEE beans used in this video were from Kaffeerösterei Rechenauer: www.rechenauer-kaffee.de/de/Espresso-Classico-1000g

[@jmoore9806]

@@TomsCoffeeCorner yeah sooo much crema....can you please show us your coffe grind setting? Alot of people can't get nice thick slow flow from a gaggia classic pro? ..... kzbin.info/www/bejne/aZvNhausetmFnac

[@is.ninomis]

Did you notice any difference in Crema amount..?

[@TomsCoffeeCorner]

Oh boy, I don't quite remember. I think they were quite similar to be honest.

[@abcabc-bu9wn]

if I grind finer and extract on 12 bar, will it taste the same with 9 bar extraction with slightly coarser grind?

[@TomsCoffeeCorner]

That's hard to say. The finer you grind, the more difficult a homogeneous extraction may become. I would suggest trying it out, and taking some notes. You will need a fine grind either way, with both springs...

[@user-qb1fs3vl2m]

What scale is that? Would love to have a timer on mine

[@TomsCoffeeCorner]

Hey E, it's this one: ► Timemore Scale: geni.us/TimemoreBlackMirror (worldwide Amazon link)

[@rodrigoastudillo7784]

When modifying the bar, can the machine break?

[@TomsCoffeeCorner]

No, but you have to be careful, not to tweak anything. Just be gentle with the mod. I have heard of people accidentally breaking the plastic OPV when removing the tube.

[@bwrrt32]

Did you ever do the dimmer mod for dedica?

[@TomsCoffeeCorner]

Hey Brennan, not yet. There is very little space for a dimmer on the Dedica. I have not found a cute little one to integrate as of yet.

[@bwrrt32]

@@TomsCoffeeCorner copy that. Thanks for the update!

[@ThrillLevel]

Why did you calculate the start of time from the start of the machine?

[@TomsCoffeeCorner]

Because that is when the brew process starts. The coffee puck is at that point confronted with water, swells, and starts absorbing the incoming water. Eventually, the pressure threshold of the coffee puck is overcome by the water pressure, and coffee starts dripping out. But that first part of the extraction belongs to the whole process as well, in my opinion.

[@ThrillLevel]

@@TomsCoffeeCorner Thank Is this amount for double or single and how long is the brewing time

[@bazbazilio]

Hello! what is the length of the spring at 6.5bar?

[@TomsCoffeeCorner]

Hi! Here is the breakdown: 12 bar spring: 23.6mm long and wire strength of 0.6mm. 6.5 bar spring: 23.9mm long and wire strength of 0.5mm. 5 bar spring: 20.1mm long and wire strength of 0.5mm

[@bazbazilio]

@@TomsCoffeeCorner thanks for the answer!

[@abc-cl3rb]

but was there actually a taste difference and in what way?

[@TomsCoffeeCorner]

Yes. If you lower the pressure, you can get that nice gooey espresso coming out. I find it to be less harsh and more well rounded.

[@datooo23]

You have my sub ser

[@simonmonty7171]

I might be wrong but I feel like having less pressure means grains has more time to soak and probably have to adapt the the roast level you like. Ie: light colored grain would be better with lower pressure since it's tougher to really extract the full wanted taste out of thse than it is with darker roast.

[@TomsCoffeeCorner]

Hey Simon, you’re probably right. The lower pressures should allow a better soak/bloom. I believe the Decent community has a lot of info on this, especially with regard to lighter roasts. Cheers!

[@SiderisSpyros]

Where can I get the 9 bar spring?

[@TomsCoffeeCorner]

Howdy! It's in the description. 👍

[@SiderisSpyros]

@@TomsCoffeeCorner Thanks, Can I also use them on delonghi debica?

[@TomsCoffeeCorner]

@@SiderisSpyros No sir! They are way too big. ;(

[@noctuliusgui]

Just out of curiosity, but 40g cup of coffee weigths 60g?

[@TomsCoffeeCorner]

Hi! Where did you see that? I tared out each time, and let the extraction run to 40 grams. Cheers!

[@noctuliusgui]

@@TomsCoffeeCorner I meant if 40g cup of coffee was a 60ml cup!! It came out wrong. I've seen people saying a perfect double extraction should be a 60ml one.

[@jmsaffroy]

@@noctuliusgui Don't believe everything you hear or read, as some people conflate being loud and assertive with being knowledgeable. There is no such thing as the size of a "perfect double extraction". My doubles range from 35g to 55g, and they would all taste good in reasonably sized cups (mine are 75ml I think). Different coffees and basket sizes lead to different doses and yields, the volume of crema changes with roast type and freshness... You can't have a single size for a "double", even a "perfect" one.

[@salreus]

This video doesn't really make sense if the grind isn't adjusted for each spring to get close to a 30 second pull. Saying a 17 second 12 bar pull doesn't taste as good as a 23 second 9 bar pull isn't telling anything. A 17 second 9 bar pull isn't going to taste as good as a 23 second 9 bar pull. So what have we accomplished with this? Does it taste better because you switched from a 12 bar to a 9 bar or does it taste better because you are closer to a 30 second pull? I am not saying a 9 bar isn't the way to go. just saying if one was to compare, then trying to get all shots at the same pull time with respective springs is what should be done.

[@TomsCoffeeCorner]

Hi Salreus! Touché. But the point of this video was to exhibit how the flow rates differ, based on max OVP pressure. In a future video, it would be good to aim for results as you discuss (grind altered for same flow rates), but then you’ll have to rely on my subjective palate as to what’s best. If there is interest in such a test, I could do that in the future. Cheers!

[@jmsaffroy]

@@TomsCoffeeCorner The video as it is shows that simply changing the pressure while keeping other variables unchanged has a notable effect, and that's worthwhile already. Adjusting other variables in response, e.g. grind size, to get back to a good (tasty) extraction percentage, is the natural next step, but it definitely is another step. Personally, I like explanations like I like my coffee, with high clarity. ;)

[@ALE34_]

Agreed. Obviously flow rates are going to be different. Higher pressure will push through faster, just because of physics. You can't make any taste comparisons here. You adjust your flow rate with your grind anyways when you make espresso, so flow rate comparison isn't exactly useful.

[@TvbLOVER1]

@@TomsCoffeeCorner but isn't it obvious a 12 bar would have a faster flow rate? Higher pressure, higher flow rate. Basic math no?

[@zimzum67]

Also another situation here that may be problematic is whether the GC machine has been pid modded... if not, then the temp cld totally mess up the result, like i sometimes had this thing going for too long and the extra hot temp burns and blasts through my shot (naked portafilter). Taste terrible, that!... Happy meddling!

[@Bayezid66]

Your coffee beans also very high quality and fresh…

[@donh1572]

I found the opposite then you. I get less acidity and bitterness as I reduce pressure. But then again I’m doing 1:3 ratio

[@TomsCoffeeCorner]

Hey Don, that could very well be. It will also depend on bean used and palate. 👍

[@wezzla]

What a crema tornado 🌪️🌪️🌪️ 😋

[@beauver9338]

I might be wrong, but you will not get 12.5 bar if your grind is too coarse. And I also think that if you grind fine enough to push the pressure up to 12.5 bar while extracting, you might get perfect extraction also depends on when you stop it (brew ratio).

[@TomsCoffeeCorner]

Yes, that is right. 12.5 bar is the absolute limit. With a normal dose in the portafilter, you are probably talking 9-10 bars. Would be my guess...

[@sorincotoi8823]

I need a coffe right now 😂

[@ronnyskaar3737]

Much easier on the Gaggia than the Dedica.

[@badreddine2651]

small things, make a defference ☺

[@dejedejsson]

Your measurements differ from what I have seen on the reddit gaggia forum? Full length 19 mm. Wire diameter 0.68 mm Outer diameter 7.08 mm Inner diameter 5.45 mm

[@TomsCoffeeCorner]

I am not sure, as I am on vacation. I used the Shades kit on this particular machine though.

[@robertbeck3403]

Starbucks!!!!

[@TomsCoffeeCorner]

??

[@traveler.]

Your experiment is completely wrong in many ways. Anyway, it counts or I try !!! Very nice video quality

[@TomsCoffeeCorner]

Thanks for your feedback!

[@fvgoya]

So, it looks like the “best one” is the 9 bars…???!!!

[@TomsCoffeeCorner]

For my taste, yes. But some like the 5 or 6.5 bar springs for turbo shots.

[@Altroante]

Good video and good editing. My only advice is that you honestly really need a better mic - the quality of the video really really suffers from it. Also, you're really close to the camera. If you watch some of the other coffee channels (as an example), you'll notice the person on camera stands further. Being "up in your face" is sort of awkward. I'm not sure how much filming space you have, but being able to see you from waist and up would make things feel a lot more professional and less awkward. And also, we see a scale for 12 bar and 9, but not for 6 bar? That's just odd. Like, why?

[@TomsCoffeeCorner]

Hi there! Thanks for the constructive criticism. I would like to improve the video/audio quality over time. Going back over the video, I see that I used a Speedlink mic, instead of the Rode. They both have cords that are a bit too short, that is why I am too much in the frame. I was thinking of investing in the Rode wireless mic in the future, for better framing, and hopefully good sound. By the way, do you mean the reverberation in the sound? Or something else? As for the scale, it is missing for the 9 bar, good catch on that. I have it in the project, but somehow it apparently didn’t export. Shoot!

[@danknoize]

This comparison is meaningless for multiple reasons: 1: the actual flow rate is determined by the hole size of the water inlet (aka gicleur/jet), not how much espresso you get out; 2: the amount of espresso produced (what you call flow rate) from each of your shots is determined by your grind size; 3: the grind size and espresso yield were not adjusted for each spring to achieve ideal shots. It is a shame that this shows no recognition for the variables that need to be adjusted by changing the brewing pressure. you can actually get great espresso at all these brewing pressures. The roast development is probably the best factor to determine what spring to use.

[@TomsCoffeeCorner]

Hey Dan, I understand your points. Others have mentioned that I should do a follow up video with the shots dialed in for each spring setting. This video was kind of aimed at the visual difference of the flow at different OPV pressures. But you are right, that each spring should be able to provide a good shot when dialed in properly. Thanks for your feedback.

[@rgd37]

this test is very flawed as your grind size dictates, and your grind is way off! Sorry

[@TomsCoffeeCorner]

Hey Robert, thanks for your feedback. The intention of this test is to show how the springs affect flow rate, while keeping the grind size the same.

[@checkwhatsleft4565]

Flow rate, well, you should've measure the input flow rate(blank shot), starts timer with first drop of water out, go 20 seconds for 3 times, divid it to get a average ml/s, because your coffee bed is gonna absorb fair amount of water, extraction flow rate is different topic, I've seen uneven extractions from u, quite often, the extraction stream swings that indicators uneven extraction, a bit of more work on ur puck prep, and high pressure is needed because of pressurized basket was, well, has been a false information, because higher the pressure will not get coffee liquid through it if it goes beyond 10.5bars, it will slow the flow rate down and chock the machine, I think nowadays, most people should've experience it that(a little bit finer grounds will chock machine if it was the combo of non OPV machine with pressurized basket).

[@TomsCoffeeCorner]

Thanks for your feedback. What purpose does it serve to know the flow rate without any resistance?

[@checkwhatsleft4565]

@@TomsCoffeeCorner It dictates the 25-30s rules should be applied or not, above 6ml/s, 25-30s rule doesn't work anymore, higher the flow rate causes faster extraction, and way higher flow rate makes terrible shots, that's why many rotatory pump machines have to install the flow restrictor to slow it down, otherwise it ruins the extractions.

[@TomsCoffeeCorner]

@@checkwhatsleft4565 Ok, well I just checked the flow rate with no resistance at all. I get 180g in 20 seconds, so 9ml/s. Is this normal for the Gaggia with Ulka pump? I currently have the 5 bar spring installed, but with no resistance, all the water should be exiting the group head, and none going back into the tank.

[@checkwhatsleft4565]

@@TomsCoffeeCorner That was too higher, but it wasn't the highest, I believe that Nuova Oscar II took the crown in term of input flow rate, it was 3 seconds 150mg, xD.

[@TomsCoffeeCorner]

@@checkwhatsleft4565 Hmm, I guess I would have to install a dimmer to reduce the flow.