10 Mil after dissolve in water

June 2024, any updates mate?

I'm really sorry, and this is asked a lot, there's no way for me to tell you that. Preservatives are typically legislated - there is a legal maximum amount you can put in a product, and that changes from country to country. You have to check your local laws. Other than using what your maximum is, I can't say. Preservation requires acidity, so make sure you have that - below 4.2 pH. Then the way you make the product will impact it's preservation. Hot brewing to above 85C in clean vessels? That will have a different result from cold brewing in less sanitary vessels because of the amount of microbes present in a cold brewed tea compared to a hot brewed tea and their environment. I've seen cases where maximum legal levels still don't work because there's too many microbes to combat. So, check your local laws, get your pH down, then see if there's a taste impact, and then try it and see what happens.

'Stale' is quite a vague term, and it could be a number of things. It could be microbes as you suggest - spoilage bacteria or potentially yeasts. It could be due to oxidation too. Try adding a little ascorbic acid (vitamin c) powder, or even a juice with a high vitamin c content: that should help reduce oxidation. One way of having a good guess if it's oxidation is if there is a colour change; it will normally turn more brown in colour if that's the case - like an apple when it's been cut and left open to the air. If you put lemon juice on your cut apple then it stops the browning/ oxidation process by supplying anti-oxidants in the form of the aforementioned vitamin C present in the lemon juice. Make sure the container is sealed so that no more air, and therefore oxygen, can get in to it too. If it is due to microbes then preserving it will help, but each country has a legal limit to how much preservative can be used, and I don't know where you're from, and wouldn't know the name of your countries regulatory body to find their rules, but they will publish it online somewhere. You're looking for 'Benzoic Acid' for Sodium Benzoate, or 'Sorbic Acid' for Potassium Sorbate. As a rule, if you're new to this then I would recommend using a combination of the two, which might have a lower maximum amount of each when used together - it does in the UK/EU. The easiest way, however, is just to heat it up in a pan to 85C and then put it into a glass bottle *while it's at 85C* with an airtight lid, then lay it on its side to get the lid hot too. This will be preserved until you open the bottle, at which point you would need to refrigerate at. Hope that helps!

@@TheFizzacist thank you very much sir for acknowledging and ideas.