95. Food Safe Pottery - How to make Pottery Food Safe

[@Heartwing37]

That pit fired bowl is incredibly beautiful!!! But the blue, black and white bowl is gorgeous too!

[@deMibPottery]

Thanks a lot :-)

[@komarpaloma]

Thank you SO much, this is one of the best and understandable explanations i have heard so far and I extremely appreciate your honesty! In Germany the law says, that every ceramic container that gets in touch with food and beverages needs to get tested in a laboratory. But not only commercial work, also things you give away to your friends. Unfortunately this is mostly known to potters or ceramicists with a traditional education. Everyone else either never heard of that or does not really care, because that's also what they are getting told. All good, if the term "food safe" or also durable or even "sustainable" would not get thrown around that much without knowing about the basics of the material. Things such as vitrification are not any topic in the new pottery courses in urban environment, nor would many people see if a glaze actually fully melted. I had myself experienced drinking my juice out of a cup with an alleged functional readymade glaze and immediately spitting it out again. The supplier said, that they of course test potential leaching, but only with one type of acid. After that i got back to only glazing the inside with my self-mixed transparent glaze. The German regulatory office and health department indeed sends employees over to pottery markets, that's why those on the radar of course feel pressured to let their functional work get tested. Although most of them know what they are doing. New design markets or fairs on the other hand are not anywhere close to that radar, which of course decreases the need to take care of it. But especially here those technical terms get attributed to the ceramics. And yes, I indeed do find this a little bit problematic. Please do not get me wrong, i am all for making ceramics accessible for everyone. But acting as if there is nothing more to learn than throwing pieces or handbuilding them to be able to responsibly work with this material does not do enough justice to this craftmenship.

[@deMibPottery]

It is indeed complex and unlike what many think not a global standard

[@Ingefee]

Ceramics Material Workshop on Cone 6 glazes gives a fantastic chemical explanation on what makes glazes food safe. Well Boron in the glaze is one factor and a Bristol Glaze is another positive factor. Bringing down the melt temperature with fluxes will cause glaze degradation over time. He says that testing your pots in the dishwasher over time is more accurate than the acid test. A great workshop indeed!

[@deMibPottery]

Just keep in mind, as I point out in the video, that food safe requirements is not a global standard

[@Ingefee]

True, but in time this will change with this new knowledge about glazes.

[@BasilWallace]

Liquid Quartz likely needs to be re-applied routinely to keep it food safe as it will be worn down during use. I wouldn't rely on it to classify anything as food safe. As you said, that pit fired bowl likely wouldn't pass a strict test, and you'd be correct. ;) As for un-glazed porcelain, you really need to look into the clay itself and see whether it's advertised as 'self-glazing'. Self-glazing Porcelain is certainly food safe, but with that said a completely vitrified porcelain body is completely vitrified, right. What we talk about with food safety is whether there's going to be any harmful leaching, and will the body itself harbour mould over time. The math on material leaching from a glazed body shows you really shouldn't be worried about leaching. For poisoning to occur from a particular material you would need to ingest on a single day far more of that material than is available in your mug, bowl or plate... Or all three

[@deMibPottery]

Actually, the Liquid Quartz does prove to work far longer than the average bowl or plate survive. Even in restaurants, used daily.

[@melrussell7830]

Wow this was a bonus Mikkel, an extra video 😊 Funnily enough I am reading Mastering cone 6 Glazes and they have broached this same question of leaching and gives you a % of copper, cobalt and rutile leaching and with a few glaze recipes that are recommended 😊

[@deMibPottery]

Thanks, as much as I love John Britts work yand books you should kerp in mind that he is not covering the legal aspects of food safe pottery and the fact that standards for this are not global

[@melrussell7830]

@@deMibPottery I have got Mid-Range Glaze by John Britt, but I was meaning John Hesselberth & Ron Roy Mastering cone 6 Glazes It’s a brilliant book, you should get it as they are very knowledgeable on glazing 😊

[@deMibPottery]

Thanks. I will look it up. However, keep in mind that glaze chemistry is just one aspect. Clay, application, fire and different local lavs are important too

[@neilahalter9663]

Thank you for another great video and I agree. You could always leave lemon over night. Slit of glazes does let you know if it's food safe nowadays. Thanks again

[@deMibPottery]

Thanks. Yes, but only to some degree, not legally and not covering all issues :-)

[@sandraleenerts6805]

Thank you for the valuable information.

[@deMibPottery]

Thanks 🙏

[@maryglancy9024]

I do agree with all the points you make it was very useful .i have never heard of the sealent you mentioned how do you spell it thanks for vidio

[@deMibPottery]

Thanks :-) liquid quartz madeofaustralia.com/liquid-quartz/

[@m4y4r4]

This video is very precious, obrigada!

[@deMibPottery]

Thank you too!

[@DunoonVanRijn-dx1hr]

I assumed once bisqued fired that it was food safe afterwards but by using chemicals on the clay to force a colour outcome makes the elements unsafe.

[@deMibPottery]

It depends. Glazes are also chemicals. It's not that simple :-)

[@aartmark]

Back in the 1970s there was a big concern with lead being used in pottery. I think most lead has been eliminated in glaze recipes after that concern. Also, a main concern then was raku pottery and most potters, if not all, have agreed that that isn't food safe. I have some cone 10 clay that I have fired to cone 10 and is vitrified. I have used some glazes on that clay that crackles. These are glossy glazes and are on pieces that are cups and bowls that would be used for foods and drink. Because the clay is vitrified, what is your opinion about food safety of these pieces? I live in USA and sell pots in small amounts. Also, I see in some videos of traditional potters in some countries that have fired pots at low temperatures for centuries and used them for food and drink. Thanks for all of your videos.

[@deMibPottery]

Yes, as I mention it is indeed not a simple issue 😁 If there are cracks in the pots I think most would assume they are not fully food safe as bacterias can hide in them.

[@aartmark]

@@deMibPottery Thank you.

[@gabriellame1815]

Thank you so much! It is an excellent video! I made a cup, covered with my own crystalline glazes in and out, then fired on 1,200C with a 10min hold. Traditionally we say the crystalline glazes are not food safe. I did the lemon test, nothing happened. Now I have no clue - is it food safe or not? 🤷‍♀️

[@deMibPottery]

Thanks :-) I could not say for sure. Also, it depends on which country you are in and which laws they have on food safety. Personally, I would not be afraid of it. Food is only short time in a cup. It's not for storage. But if you sell it you may want to add a disclaimer.

[@gabriellame1815]

@@deMibPottery Yes, you are right, thank you so much!

[@JetcannonM]

real talk

[@deMibPottery]

Thanks :-)

[@chocolatejwoo475]

so plastic is better than ceramics for food storage? (ofc not for microwave)

[@deMibPottery]

That depends on what ceramics and plastic you compare :-)

[@margotpenney8608]

Hi, amaco glazes have glazes say they are food safe so now I'm confused!!! You pronounce quartz as " korts", lol

[@deMibPottery]

If they are they are not tellung the truth. Food safe where? The US? Denmark? No matter the application, surface, clay or fire? Sorry, buts not that simple!

[@lorihry6236]

@@deMibPotteryI know in Canada the glazes are sold as ‘food safe’ and ‘not food safe’. But I completely agree with your statement that not all glazes can be food safe with all clay bodies, and one’s application may not be done properly. Also, if the expansion rate of the clay and glaze is not matched, crazing will happen, leaving the piece not food safe, even if it’s labelled as such. Great video!

[@emilieneubauerova4699]

😉😊👍🤏🤗🍀🍀🍀👍✊👋

[@deMibPottery]

Thanks :-)