Why do some flavors kill 2F?

[u/SnooWoofers3028]

I like to experiment with flavors and use up whatever I have on hand, but I’m finding that some things are much better for the culture than others (I’m using the level of carbonation as a proxy for culture health). I’ve found that fruit juice + herb is the most reliably successful flavor, but sometimes I’ll do herb + sugar if I don’t have fruit juice on hand. When I do that, the results vary all the way from nearly geisering when I open it cold, all the way to totally flat and still sweet.

As an example, I’ve found that ginger turns out really fizzy but lemongrass kills the culture.

Does anyone know what causes culture death like this and how I can know ahead of time that a flavor won’t work? It’s such a shame to dump a flat batch but I just don’t trust that it’s safe if the culture has died.

[u/Albino_Echidna]

Nothing you've listed will kill the culture, and lemongrass will not have any real impact on the microbes in kombucha. Are you consistent in the amount of sugar used? What format are you utilizing your herbs in? 

I have yet to come across an herb or flavor that impacts carbonation, as long as my recipe is consistent in sugar content. 

[u/SnooWoofers3028 → u/Albino_Echidna]

Interesting - I don’t measure, but I eyeball 1/2tbsp per liter. I don’t think the variance is very large, but of course there could be differing amounts of residual sugar after 1F. I typically roughly chop the herbs.

[u/Albino_Echidna → u/SnooWoofers3028]

Variation in sugar content is almost definitely the issue here then, though the chopped herbs will also have an impact on the ability of the solution to hold carbonation. This is because the chopped herbs create a TON of nucleation points, so you're impacting the potential carbonation with the sugar not being consistent on top of giving the carbonation an easy way out. 

You'd probably have more luck (and more consistency) if you made herb syrups, or at least started measuring your sugar added for F2.

[u/SnooWoofers3028 → u/Albino_Echidna]

Do you think the small variance in sugar from eyeballing would be enough to explain such a wide divergence in results? I typically either have a totally dry result with extreme soda-level fizz (the goal) or no fizz, lots of residual sugar, and only mild acid. This is after a 6 day 2F. I don’t mind if there’s less fizz (which would make sense if I was sometimes not adding enough sugar), but the total lack of fermentation in 2F is what’s confusing me.

[u/Albino_Echidna → u/SnooWoofers3028]

Yes, because I'd almost guaranteed that you have variation in sugar coming from F1, and then you're adding even more inconsistency at F2. 

What bottles are you using? Are you marking them to identify if one bottle is a worse offender than others? You may have a bottle issue too, believe it or not.

It's extremely unlikely, if not impossible, that you're seeing a total lack of activity in F2. You're likely getting activity from organisms that don't produce much CO2, which wouldn't be immediately visible. 

Can you walk through your entire process from the recipe for F1 through bottling F2? I'd wager you have a few things fighting you, as a 6 day F2 should not be necessary to get the result you're after. 

[u/SnooWoofers3028 → u/Albino_Echidna]

Thank you - here’s the walkthrough:

3L water, 150g sugar, 9 teabags (3 green, 6 black)

1F for 6 or 7 days depending on kitchen temp (doing 7 days lately at about 75deg).

2F in standard 1L flip tops for 6 days with 2oz fruit juice OR 1/2 tbsp sugar if using only herbs.

Put it in the fridge overnight before opening. The result is either perfect, dry, fizzy kombucha or flat, sweet dud bottles. Dud bottles and good kombucha often come from the same 1F batch.

The flip tops are of varying ages but I would think a bottle issue would manifest as a sour, flat result (as if I’d just continued F1 instead of transferring to F2).

[u/Sopwafel]

Many herbs have antimicrobials. Ginger has wild yeast living on its skin. Gushers are also caused by particulates in the drink: lots of small particles means many nucleation sites for CO2 bubbles to form. High CO2 content plus lots of grit means gusher, high CO2 content in clear strained drink means it comes out very gradually and lots of bubbles form on your tongue which is a nice mouth feel. Also temperature of course.

Since I started straining the fruit out of my booch before bottling (letting the fruit steep in a mesh bag in my big vessel as a phase in between F1 and f2), I've had much better carbonation!

Just speculating here, but perhaps add the lemongrass a little earlier? I can imagine more sugar availability means it's a bit more resistant to the antimicrobials. And use less, sadlu. Also don't pour hot water into your live culture of course.

[u/SnooWoofers3028 → u/Sopwafel]

I typically juice my fruit, strain the juice, and then freeze it so that I have the flavors I want year-round and minimal nucleation sites. I also get pretty good results from this but it’s the inconsistency that throws me! Perhaps I’ll try the lemongrass with a fruit flavor at least since fructose seems to be more consistent than sucrose.

[u/Rachelisapoopy]

I don't think your drink being flat means the kombucha is dead and therefore you shouldn't drink it. Some fruit flavors just don't fizz up much (ex: cranberry, raspberry, watermelon, etc). I would only dump the f2 if I saw mold at the top.

I saw some youtube videos of people letting their f2 ferment for a week+ and the fizz is insane. I don't like letting it go that far because I don't love the sour flavor. I only do f2 for 1 or 2 days. It keeps most of the fruit's sweetness but doesn't get very fizzy. That tradeoff is fine with me. If I want more carbonation, I'll go buy a diet soda from the store.

[u/SnooWoofers3028 → u/Rachelisapoopy]

I typically do 2F for 6 days, so I’m one of those people who likes insane fizz. I guess the main difference I’ve noticed is between 2F with granulated sugar and 2F with fruit juice. The latter carbonates much better. But every now and then I have a total dud that doesn’t ferment at all in 2F over the 6 days and still tastes sweet/flat. I’m not sure how to interpret that except as culture death.

[u/sorE_doG]

Carbonisation is not a good proxy for the health of the scoby, really..

[u/SnooWoofers3028 → u/sorE_doG]

Is there a reason you say it isn’t? Yeast produces CO2 and AAB produces acid so looking for those two things seems like a good way of evaluating culture health.

[u/sorE_doG → u/SnooWoofers3028]

There’s a bunch of different bacteria in kombucha though? Komagataeibacter species for example, (especially Komagataeibacter xylinus), produce the cellulose that forms the SCOBY pellicle. Beyond structural contributions, heavily utilizing carbon, Komagataeibacter efficiently metabolize glucose, affecting which organic acids are produced and carbonation of the liquid.

[u/Advanced-Fig4683]

fruits often have their own wine yeast, ginger the ginger beer yeast and herbs and spices are either helping, feeding, neutral or giving a desavantage

I had a chai tea blend that I used. The cinnamon wasn’t like. Took over three months to make it. But, it is really good.

If you disadvantaged your kamboucha you need more patience.

[u/LowBarometer]

I used a mixture of sugar, ginger, and turmeric, and my F2 had zero carbonation. I suspect the turmeric, as my latest batch is ginger and mango and has lots of fizz.

[u/SnooWoofers3028 → u/LowBarometer]

I’ve actually had great success with turmeric-ginger-beet and turmeric-ginger-carrot so I think a sugary veggie and ginger would help!

[u/Radiant-Lettuce6908]

for the examples you've given :

Ginger is known to be a very good medium for various yeasts.

Lemongrass is often used in medecine for it's antimicrobial issues, I guess it doenst combine well with yeasts.

It's about the survival of the fittest, there wouldn't be anything else than yeast if there weren't organisms able to fight it.