Rescue my tepache!
July 20, 2021 5:36 PM   Subscribe

This first time tepache brewer put a silicone airlock on her tepache. 36 hours later, no bubbles are visible and no upward pressure on the airlock indicating CO2 production. Now I find out that tepache is an aerobic ferment, not anaerobic. Can I save this batch?

Contents of 40oz jar are the skin of one organic pineapple that I gently rinsed in cold water, half a cup of brown sugar, a cinnamon stick and a couple of cloves, plus water to fill.

It currently smells vaguely pineapple-y. No sulphurous or rotting smells are present. The pineapple doesn't appear to be rotting and is pushed under the water with a glass weight.

I've swapped the pickle pipe with a clean cloth + rubber band in the hopes that fermentation will start now that the yeast has some oxygen.

Will it be safe to consume if it does begin fermenting?
posted by burntflowers to Food & Drink (6 answers total) 2 users marked this as a favorite
I've never had this particular issue and I hesitate to make blanket statements about fermentation safety but I've made a lot of batches of tepache and always found it very forgiving. I've left it fermenting for anywhere from two to eight days, with all kinds of different amounts of sugar or water added, and it always turns out fine. Sometimes it does take a few extra days to get funky and tasty, so that might be your issue.
posted by LeeLanded at 7:02 PM on July 20, 2021 [1 favorite]

It sounds like you're relying on natural yeasts associated with the pineapple rind. There are all sorts of plausible reasons why natural yeasts may be missing or otherwise inactivated.

When I ferment, the addition of defined and activated yeast is a safeguard against other microorganisms - by producing ethanol early, it outcompetes against detrimental microorganisms and by continually producing ethanol, prevents the outgrowth of other microorganisms.

Look for "floating colonies" or sliminess - these are hard NO characteristics and the ferment should be discarded.

If the liquid turns cloudy, that's a sign of microbial propagation. If it's yeast, great, but other microorganisms can produce the cloudy look. When the liquid starts clearing (from the top down), that means the alcohol content is exceeding the tolerance of the yeasts. If you let it keep going, eventually the liquid will clear and a sediment will form at the bottom of your vessel as almost all of the yeast die and sink.

This is not traditional, but I like using "champagne yeast" from brewing suppliers. Wake them up in a little warm water and sugar. Spike what you want to ferment with it. Champagne yeasts are bred/ selected not to produce too much "other stuff" that can taste poorly, and also bred/ selected to tolerate higher alcohol concentrations. You shouldn't need to use the entire packet; back-calculate how much you want to use depending on the volume you want to add it to.
posted by porpoise at 8:07 PM on July 20, 2021 [2 favorites]

You should be fine, it's fairly forgiving, agreed. When you're relying on the natural yeasts, it'll be more variable in how long it takes to get going.

I wouldn't worry about it getting an anaerobic period.
posted by CrystalDave at 9:06 PM on July 20, 2021

I haven't made tepache but I've fermented other fruit juice things. I stir and splosh the batch at the beginning to aerate and that that apparently is enough oxygen for the full course. If you used tap water without standing you've got plenty of oxygen (maybe some chlorine too), if you even poured the water splashily I think you're fine -- I know people who don't do anything special to aerate.

I think you're probably waiting on exponential growth of your yeasts from the fruit skin.
posted by away for regrooving at 9:35 PM on July 20, 2021

I've fermented apple juice (with added yeast) to make soda and it fermented just fine in a sealed bottle. I obviously wanted to keep the CO2. I agree with others that it may take a little longer but that no, you didn't ruin anything.

I understand that tepache is mainly yeast (plus some bacteria?), so I don't think there's any danger in using an airlock since brewers commonly do this. It probably ferment faster with a fresh supply of oxygen.
posted by O9scar at 1:10 AM on July 21, 2021

I got impatient with a batch of tepache at pretty much exactly that point and decided to help it along by pitching in a sachet of champagne yeast I had lying around.

Do not do that. Oh my goodness was it foul. Bready, thick, and foul. Just give it time.
posted by dr. boludo at 5:42 AM on July 21, 2021

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