New Scoby too sour

[Milena]

I don't have very long experience with kombucha, but I did few batches with a bought skoby and they turned fine. I even started one from scratch with store bought kombucha and it was fine too.
Unfortunately, I was away for a while and I lost my scoby, so I try to start it from scratch again, but somehow, by the time the scoby get formed /even a very thin one/, my brew turns quite sour. The fermentation goes too far, but the scoby is not well formed yet. There is no mold, the scoby is clean, it's just to sour. I try this twice with different kombucha for starter, but the result is the same.
Can someone, please, advise me what might be the problem and what should I do to prevent it from happening again?

 

[Yooper]

Get a new SCOBY? The one you have seems to favor acetobacter, the bacteria that makes vinegar.

 

[Morrey]

Obviously there will be those who use a variety of methods such as buying a bottle of commercial kombucha to get a new scoby formed. Some folks will pitch vinegar to get the ph down some to ward off unwanted bacteria. While this may work ok sometimes, it may not work ok other times and you've wasted time, effort and materials.

It may be well worth your time to buy a scoby from a place like Amazon in which the scoby comes in a pouch filled with kombucha tea which adjusts your ph to safe anti-bacterial levels. It costs like $7 and I was drinking tea in 10 days.

 

[Milena]

Thanks

 

[Scientific hippie]

Hi! I just joined. I have been brewing kombucha for a few weeks; I really enjoy it. I started out with two different scabs from two different companies. The first batch from each was great. The second batch from one was sulfurous; I asked the company about it and they said they had never heard of it. Meanwhile, I was getting a baby scoby atop the good one. I put it in a scoby hotel for a few days. Ten days ago I started a 1.5 gal batch with the old scoby; it finally tasted good today and I decanted it for secondary fermentation with some blueberries added. I started a 1 gal. batch with the baby scoby last weekend; today (Wednesday) it is very sour. I bottled it with crushed peaches, and added some sugar. As I set up to make new 1.5 gal and 1 gal batches, I switched some of the starter tea from one jar to the other and vice versa; I'm interested to see what happens.

 

[Yooper]

Hi! I just joined. I have been brewing kombucha for a few weeks; I really enjoy it. I started out with two different scabs from two different companies. The first batch from each was great. The second batch from one was sulfurous; I asked the company about it and they said they had never heard of it. Meanwhile, I was getting a baby scoby atop the good one. I put it in a scoby hotel for a few days. Ten days ago I started a 1.5 gal batch with the old scoby; it finally tasted good today and I decanted it for secondary fermentation with some blueberries added. I started a 1 gal. batch with the baby scoby last weekend; today (Wednesday) it is very sour. I bottled it with crushed peaches, and added some sugar. As I set up to make new 1.5 gal and 1 gal batches, I switched some of the starter tea from one jar to the other and vice versa; I'm interested to see what happens.

It sounds like you've got some contaminations going, or a very high temperature or some reason you've had it "very sour". Most good SCOBYs and starters have a good combination of bacteria and yeast to make it tart, but not sour, and to make it taste pretty darn good right away.

I'd consider buying a new starter from the company that gave you good results, and for subsequent batches make sure to use very sanitary equipment and techniques, and to cover with a paper filter (like a coffee filter or paper towel) and keep it at 75-77 degrees or so if at all possible for the best continous results.

 

[Scientific hippie]

Aha! I wonder if it's the temperature? We've been running in the 90's outside, 80's inside. The top of the refrigerator is probably warmer than that. I'm going to check the batches daily; if the sour thing happens again I'll get a new scoby (it was expensive! $35!)

 

[MWS]

Try a less than ideal tea with this strain such as rooibos. In my experience, this tends slow fermentation down and give a more cider like character. After that batch, go back to the black tea to give the scoby a chance have another healthier fermentation. I've always had luck with having my starter tea be from a fresh store bought strain that I enjoy.

 

[Scientific hippie]

That's a very interesting idea! As it happens, I just bought a three-tea sampler. The black tea was blended with rooibos; I usually use a black-and-green blend that tastes great. I have already started two batches after trading starter tea; on day 1, both have a pH of 4, but the sour one already tastes more sour than the tea made with the older scoby. I plan to follow them very closely every day; I have since bottled the sour batch I talked about and added crushed peaches; last night I also added sugar, and it tasted great today so I have refrigerated it, while the other isn't too tangy and needs more time. When I have finished these batches, I will try your idea with the "less-than-ideal" tea with rooibos. I may just end up naming the two scobies (Why does the spellchecker always try to make it "scabs"?) Speedy and Slowpoke.

 

[RPh_Guy]

Sourness is [almost definitely] caused by the bacteria in the SCOBY.

Decreasing the fermentation temperature should reduce the acidity, especially over repeated batches.
This is because yeast don't mind cooler temperature but bacteria generally prefer heat (especially body temperature).
I don't know what the ideal fermentation temperature is and I'd think it varies by SCOBY. However, the bacteria should be pretty well inhibited under 75°F. Down to about 65°F would be reasonable if you don't like sourness.

If it tastes like vinegar, reducing air exposure will also help because oxygen is required to make acetic acid.

 

[Scientific hippie]

We don't have central air conditioning, so I am relatively at the mercy of the weather. Anyway, mixing of the starter teas may have helped; the "fast" scoby brew tasted less sour today, and the pH is still 4.0. Meanwhile, I have refrigerated my 12-day brew after just a few days of secondary fermentation; most of the bottles have blueberries. It tastes good! It's not fizzy; I think I will work on that after I have a better handle on the fermentation.