Stopping fermentation in soft drinks

Question

Does anyone know how they manage to stop all these (naturally) fermented drinks sold commercially from fermenting once they are bottled? I’ve seen kombucha bottles coming from another part of the world sold in local large supermarkets. Even assuming ideal transport conditions (cold temps) how can they maintain alcohol levels low enough? Do they treat them thermally or chemically?

I know a refrigerator helps slow down the fermentation process but even so, my ginger ale keeps fermenting at 2 Celsius to an extent that after 3 days it’s quite alcoholic, one can actually taste the difference. That makes me think that simply storing / transporting them in cold temperatures isn’t enough and that there’s more going on, surely there are some industry standards in this field.

Does anyone know how do this aspect is handled in the fermented drinks industry?

Answer 1

Cold alone is not really an option, since yeast will not die but become dormant, and could be reactivated after heating a little.

There are a few ways to acheive this:

Pasteurization
This will kill the yeast, but heating could affect the final product in some cases.

Filtration
A very fine filter can remove yeast particles.

Sweeteners/Less sugar
Adding non fermentable sugar allows to keep some sweetness. Less fermentable sugars will produce less alcohol.

Answer 2

Commonly in wine and apple cider production, potassium sorbate and sodium metabisulfite are used to control yeast (and bacteria).

The potassium sorbate stops the yeast from multiplying, while the sodium metabisulfite kills (most of) the yeast.