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Succession and Why We NEVER Continuous Brew

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Succession and Why We NEVER Continuous Brew
A Common Problem :

My Kombucha tastes like vinegar.

or

My kombucha ferments so fast I can't control it.

 

 

Time and time again, it is because they were trying the continuous brew method. Sometimes they only continuous brewed for a few weeks before noticing a dip in quality. When they attempted to revert to batch brewing with the same culture, they discovered they had fundamentally changed the culture and could not get it back to its former glory. Here is our educated assumption of what is happening....   Succession is the observed process of change in the species structure of an ecological community over time. Many multi-species ferments are successive in their microbial activity meaning that in the beginning of the fermentation process, a certain species or set of species is active. As their activity changes the composition of the substrate (making it more acidic, for example), the conditions become unfavorable to those first pioneering species. They grow sluggish and eventually halt their activity while the new conditions they created are prime real estate for the next wave of species to succeed. And this can happen several times throughout a fermentation process.  

The succession process in fermentation is highly studied and documented in sauerkraut. In the beginning of sauerkraut fermentation, Leuconostoc mesenteroides is the pioneering species that gets going first. As this bacteria proliferates and its acid-producing activity lowers the pH in the crock, the conditions become intolerable for it. It’s kind of like if you keep setting up more and more kombucha brews in your kitchen, eventually it will become so overwhelmingly acidic smelling in there you won’t be able to go in without a respirator. (Believe me, we know). So, once Leuconostoc mesenteroides has chopped its nose off despite its face, other species in the crock that love lower pH conditions, like Lactobacillus plantarum and Luteimonas cucumeris, wake up and shine! They get active digesting stuff, transforming stuff, creating their own styles of acids that then lower the pH even more. They have their time in the limelight and then the conditions become intolerable to them (again by their own activity!) and they stagnate. But those low low pH conditions are perfect for the next round of fermenting bacteria to set up shop and Lactobacillus brevis begin their heyday creating their own signature acids.   With each wave of microbial activity, a new set of compounds is created and it is the layering of these compounds in succession that creates the complex health attributes and delicious characteristics of finely made sauerkraut. One would not throw a cabbage into a crock with only the last round of bacteria and expect it to yield the same delightful results as a ferment that has gone through all of the natural stages of complex fermentation . No no no.   And this explains why we don’t advocate continuously brewing kombucha. In our years of experience in home fermenting and commercially brewing kombucha, we have never tasted a kombucha made using the continuous brewing method that meets our standards for a robust, complex and delightful 'buch. Continuous brewed kombucha results in a profile that skews toward too much acetic acid. You can tell because it tastes like vinegar.   Not only that, but kombucha cultures that have at some point in the their history gone through a period of continuous brewing seem to lose the ability to ferment at the earlier stages altogether – the cultures seem to have lost the pioneering species and have become concentrated with the microbial species typical of later stages of fermentation. You can always tell a SCOBY has a continuous brew heritage by the immediate formation of the “vinegar” flavor that is characteristic of acetic acid just hours after a new batch is inoculated. This is not the kombucha that we like to drink and we think it may not have the same nutritive characteristics as those that are allowed to go through all stages of fermentation in batch brewing. We have also never seen a SCOBY recover their pioneering abilities.   If you are in the market for a new SCOBY, we highly recommend you start with a SCOBY guaranteed to have never been used to continuously brew kombucha. Your crock, palette and belly will thank you.

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  • Eric
Comments 68
  • Tony
    Tony

    Sorry in advance for the dense question I’m about to ask, but I think I’m missing something here. I was definitely having a problem with my brews having a heavy vinegar flavor. I just couldn’t get it to taste good. Long story short I am in the market to start brewing again with a new scoby soon. So, in the past my routine was to brew a 1 gallon batch, & let it ferment for about 14 days (I think this was too long now). Then at the end of 14 days, would brew another batch, bottle the first, then set up the next batch using the 2 scobys from the freshly bottled batch. The 3rd batch, I would get rid of the 1st brews scoby only keeping the most recent 2 scobys in a brew at a time. rinse and repeat. Is this what you’re referring to in regards to “Continuous Brew”? Or is continuous brewing something else entirely?

  • Matt
    Matt

    Hello,

    I guess I’ve been doing a variant on the continuous brew. I have a 3 gallon crock, and as the buch ferments to how I like it I siphon off everything except for an inch or so of liquid at the bottom and put it into growlers. Then I put the growlers into the fridge to stop the fermenting. The 1 inch brew sits for a week or so in the crock at room temperature while I drink from the growlers, then I add another 3 gallons of sugared tea and go from there. I would think this would allow all stages of bacteria to co-exist as the ph would go almost to neutral when I add the new tea.

    Is this correct, or do I need to do something different?

    Thanks,

    Matt

  • Chris
    Chris

    Hi Jackie, as for fruit flies, it’s as simple as keeping the brew jar covered – a tee-shirt type material is just fine. Many people think that cheese cloth is okay to use, but in fact the weave is too porous. Let us know how it goes, and happy brewing!

  • Jackie Edwards
    Jackie Edwards

    Well, I think you may have answered my question before I asked it. I have been making Kombucha for about 2 years, using a Scoby I originally purchased from you. I had great results. I started continuous brewing about 3 months ago, and lately my brew has not been the same quality as before. Too acidic tasting, and then this week, despite my careful precautions, one of the continuous brew jars had an infestation of fruit flies. I threw everything out, rewashed and sterilized everything, took half of the scoby from my second continuous brew jar that was not contaminated, and started again. I think now I just need to start over and go back to my gallon jar method with new scobys. Do you have any suggestions for the fruit flies? I use Tee Shirt material over the top with a rubber band securing it. My grandson made me a fruit fly trap which I set out in front of the jars, and I always seem to catch a few. They have become quite a problem, where they never were before. I usually have 3 or 4 gallon jars fermenting each week, and everyone really enjoys the Kombucha.

  • Chris
    Chris

    For the purposes of this article, I would define continuous brewing as the practice of periodically removing and “topping off” a kombucha brew without ever removing a majority of the brew. You might describe, then, “continuous batch” as removing 90%, leaving 10% as starter for the next brew, and refilling with sweet tea – though I would call this standard, and not “continuous” at all. Hope this helps!

  • Jo
    Jo

    I use an unbleached coffee filter with a Rubberband to keep the flies out

  • Bonita Fisher
    Bonita Fisher

    Wow – and you have answered mine as well, I suspect. Not so much from continuous brew, as from leaving the ’buch to brew too long, repeatedly. As in, trips abroad, busy with home and work – in fact, months-worth . . albeit at ~ 68-70 degrees. So, often I have wondered about just this thing – if I was losing certain healthful species to a plethora of low-pH species.
    Hmmm – now to figure if I must start . . again . . !

  • Deirdre
    Deirdre

    Help! What exactly is continuous brewing, and what is the correct way to home brew? I think I’m “continuous brewing” currently.

  • Lisa
    Lisa

    You said you recommended starting with a new scoby that had not been from continuous brew, but could you grow a new baby Scoby and separate it from the old one (that was from continuous bew) and be ok?

  • Ann {Created To Cook}
    Ann {Created To Cook}

    Fascinating article… And now it’s got me wondering… You know how raw apple cider vinegar is suppose to have all these health benefits and be able to help control blood sugar levels. I wonder if Kombucha left to ferment into Kombucha vinegar would have similar health benefits. I wonder if this has ever been tested in a lab. Have you guys had much experience with cooking with and using Kombucha vinegar???

  • Chris
    Chris

    Gibson, I think you’ll be fine if you’ve had success so far. Keep up the good work!

  • Gibson
    Gibson

    Great explanation of the details regarding each bacterial strains’ lifecycle and needs. Very interesting and definitely helps to better understand fermentation/brewing as a general topic.

    I have personally only been brewing since the beginning of March, harvesting my first batch (48 oz mason jar) at around day 18. The SCOBY I used was one I grew over a period of 45 days from a bottle of GT’s Original (the “non-reformulated” version). I found the taste akin to commercially-available booch, but definitely having a more vinegary taste and in general just more “raw” (both in a good way). I have a second batch brewing now with both the first SCOBY and the baby SCOBY grown during the first brew.

    Should I be concerned about my SCOBYs’ lineage, coming from that bottle of Original? Or is it safe to assume GT’s brews in batch, and thus any cultures stemming from that will be fairly healthy?

    Thank you!

  • Chris
    Chris

    Hi Matt, I’d consider this a batch method and is AOK in our book!

  • Chris
    Chris

    Absolutely!

  • Chris
    Chris

    Generally, a palatable pH for kombucha is 2.75-3.25, but really it depends on your own preference!

  • Chris
    Chris

    I don’t consider it continuous! Keep it up!

  • Michael cokkinos
    Michael cokkinos

    Sucsession brew in a continuous vessel

    I just set up a system where I brew in a spigot glass carboy then bottle everything but 2 cups for the next batch
    Add sweet tea and ferment

    Is this considered continuous?

  • Jack Wilson
    Jack Wilson

    What should the pH be? I have been using the continuous brewing method and if I leave it too long it will get a vinegar smell and taste, I just find that I have to bottle it quicker.

  • Marlene
    Marlene

    When my gallon jar is ready to bottle there is sediment in the bottom. Should it be mixed in before bottling, or discarded.

  • Frankie
    Frankie

    Hello, thank you so much for this information. Most of the web is crazy for continuous brew. We have just had our kombucha turn too vinegary too quickly from continuous brew. If we buy new scobies can we use our kombucha from these continuous brews as starter but buy new scobies? You say that you’ve never seen scobies turn back after continuous brew, but buying all new scobies would be rather costly. Is it the scobies, kombucha or both? Thanks for your input

  • Stefanie
    Stefanie

    Ah! So what about if you’re taking a break from brewing – I have my scoby in a jar and I have been pouring off half the liquid and replacing it with sweet tea every so often….just to keep it going…but this is awfully close to a continuous brew situation! Am I killing it? Thanks!!!

  • Cheryl
    Cheryl

    my buch turned to vinegar, I removed my SCOBY and saved 2 cups of liquid in a qt ziplock bag, should I wait before starting another batch, and where should I keep my SCOBY/starter? fridge or room temp? FYI I found a sticky thermometer at the pet store for $2, it is on my buch jar.

  • Blake G
    Blake G

    Very interesting article, but i’m left a bit confused with the plethora of opinions i have read on proper brewing.

    Where does this leave the SCOBY hotel? It would seem to follow logically that because they are usually stagnated for long periods of time they too would lose their ability to ferment at earlier stages. Leaving them “duds”

    Also, i have been looking to upgrade to a charred and aged oak barrel as a brewing vessel for my Jun as i’ve heard of a nice flavor being infused into the brew; But this method seems to always use a continuous brew method. Would a batch brew method still give that extra flavor with so little time in the barrel?

  • Chris
    Chris

    Hi Marlene, that’s up to you, as it’s not bad for you and it’s just spent yeast.

  • Pamela
    Pamela

    I always wondered why my batches always tasted so vinegary. Thank you for the explanation.

  • Oscar Angulo
    Oscar Angulo

    Hey chris. Here’s what i do. I make 2.5 gallons of oolong tea kombucha using one large scoby and a regular size(but multiplying) scoby. I let it ferment for 10-12 days in room temperature and then bottle it with whatever flavor my family wants. I leave about 15% for the starter batch which i start right away. so far, everything seems to come out fine. Is what i’m doing ok? will it have any effect on my scoby or my finish batch in time?

  • John
    John

    So if Continuous Brew is not a good,

    so how long do we have to wait for next batch then leave 90% of the fermented and put a new batch of tea?

    Its good to know the Continuous Brew is not good but the solution towards isn’t very clear.

  • Lindsay
    Lindsay

    I am new to home brewing and I am a little confused after reading this article. I want to describe to you my process and I would really appreciate your input:

    I use a Jun scoby and a 1.5 gal vessel with a spigot. I add about 1.2 gal of green tea sweetened with 1C of honey to the vessel and put the scoby on top. I let it sit for about 3-4 days depending on how hot it is in the house then use the spigot to bottle up my brew (I keep a little medicine dispensing cup on top and taste it from the spigot to see if it’s getting vinegary). On day 3 or 4 I bottle the tea using the spigot. I do not stir the tea before bottling it. I then reserve about a cup of it from the spigot for my next batch, discard the sludge at the bottom, rinse the vessel, clean my scobies and start again. I left the sludge in the bottom the first couple of times as my starter, but feel like there is too much yeast in it and it makes the brew sour so fast that I started feeding it to my house plants instead. Is this they way to do it? Thanks so much for your awesome website.

    One more question: My husband and I are doing a ketosis reset diet and we want to know how many carbs (approximately) are in a 16oz bottle of plan jun that has had a second ferment. If you have any input here, that would be greatly appreciated! Thanks so much!

    Lindsay Behr

  • Eric Childs
    Eric Childs

    Stefanie, the only way to store a SCOBY without it changing is to put it in the fridge along with fresh kombucha. You can keep it like that for 3 months without much change.

  • Eric Childs
    Eric Childs

    Hello Frankie, if you buy new SCOBY you should keep them separate from the SCOBY you have now. This will keep the new colony whole.

  • Eric Childs
    Eric Childs

    Lindsay, you’re doing great! This is exactly what you should be doing. I hope you are still enjoying your brew. Im not sure about JUN but tradition kombucha has around 10g of carbs per 16oz serving.

  • Eric Childs
    Eric Childs

    Hi John. The best way is to first remove your starter liquid for your next batch. Then bottle all but the last 1/2" of kombucha in your jar. That last bit is full of yeast and can be dumped. This will help keep the yeast colony in check. Rinse your brew vessel then start again using all new sweet tea, the starter liquid you set aside and ONLY the new SCOBY that formed on the surface of your last brew.

  • Eric Childs
    Eric Childs

    Hi Oscar. You’re doing great! The only improvement I would make would be saving the first 2.5cups of kombucha for your starter liquid and not your last. We dump the last inch of brew that is full of yeasty sediment. This helps keep the yeast colony in check. Also get rid of all old SCOBY and keep only the new.

  • Ola
    Ola

    I am from Russia and as I grew up my mom and grandmas all had kombucha in 3 liter jars. The different thing from american brewers is that we give a bath to the scoby ones in about 2 weeks. We take the scoby and the liquid out, rinse jar and wash scoby in water. Filter liquid through the cloth and only then make a new tea plus some old solution. We also drink it beginning from the day 3. Or later, depends on taste prefference. I have not found any info about washing a scoby on american websites…

  • Eric Childs
    Eric Childs

    Ann, great thought! I would love to see the levels of acetic acid in both apple cider vinegar and kombucha vinegar. Im sure they are much the same. We have tons of recipes using KB vinegar! Check out our book.

  • Eric Childs
    Eric Childs

    Blake, you should store your SCOBY hotel in the fridge to lock in the microbial content. It can stay unchanged for up to 3 months. After that time it is best to cycle through the SCOBY stored.

    An oak barrel can be used for batch brewing and makes some amazing kombucha. Let us know what you come up with!

  • Eric Childs
    Eric Childs

    Cheryl, you should store your SCOBY in the fridge until you are ready to brew with it.

  • Lin Mercer
    Lin Mercer

    Refrigerating VS NOT for SCOBY Hotel:
    I’m JUST starting to do my own continuous brewing at home. I had problems with mold from a gifted SCOBY (from a health food store!) that was refrigerated. My new batch is now a gifted Scoby from a local brewer who says they always throw out their “once used” Scoby and so that is what I have. I’ve read so much info on “DO NOT” refrigerate your Scoby Hotel.
    My question also is, Do I put a plastic lid on these? They are stored in half the growler and half sweet tea. I’ve been very concerned about who is reputable on this process. Yet this is supposed to be a 1000 year old ancient brew. What did they do that was successful? hmmmm.
    Thanks for any input about lids, cloth, refrigerate (check out Kombucha Kamp!) or no refrigerating. Sweet tea or just a jug of GTs?

  • Karen Cayen
    Karen Cayen

    Great site and terrific information – thank you! Please comment on the use of SCOBY hotels. I had read that storing in the fridge would kill a SCOBY and that keeping extras on hand via a hotel was a good practice. Your “pioneer” bacteria concept would challenge the hotel theory wouldn’t it?

  • Ariesbear
    Ariesbear

    Ok, my first batch has brewed for 14 days. Nice looking plump baby… clear yellowish buch.. Looks good, smells fine BUT it tastes like vinegar. That said, it doesn’t taste aweful… Winter in Wisconsin means that the temperature in my house during the day (when I am gone) is 68 degrees… At night its 72 then 68 degrees when I am sleeping. Do I need to keep my brew warmer..?

    Best Regards, AB

  • Ashley
    Ashley

    Hello! I am confused as how you make larger batches if you can only use the newly formed SCOBY each time for a new brew. The new SCOBY is much larger than the one you sent me, does that mean I can make a larger new brew and if so, how do I figure the ratio?
    Also, What purpose does keeping the old SCOBY have? Or do you not keep it?? Im so confused. LOL.
    I just made my first batch and definitely left it to long and it is vinegar, however, we drink ACV every day, so we will just drink the Buch vinegar instead. I am waiting to hear back from you before I start my new brew! Thank you!

  • Amy
    Amy

    Very informational, thank you so much! I’m definitely not going to try continuous brew now. My first Scoby is arriving next week, along with tea, thermometer, heat mat. I already have a glass jar with spigot, organic sugar, agave or honey. When saving the Scoby from my first batch, should I take it off the top along with 2 cups of liquid for the next batch? Or off the bottom and out the spigot for the next batch liquid? Would off the bottom and they the spigot get yeast in it? Do I use my orig Scoby or just the new baby going forward each time? Got cool ideas of how to “recycle” the Scoby we are getting rid of? I’ve heard of composting. What else to use the old Scoby? Thanks again. Happy brewing!

  • Joanie
    Joanie

    Thanks for clearing up this issue. NO more continuous brew for me ever…and now I need to buy a freshy from you.

  • Steph
    Steph

    You say “kombucha cultures that have … gone through a period of continuous brewing … seem to have lost the pioneering species and have become concentrated with the microbial species typical of later stages of fermentation”.

    Please help, because I can’t make sense of this. It seems logically backwards. A SCOBY that is continually supplied with fresh sugars will surely, necessarily, retain its pioneering species. By contrast, a SCOBY that is allowed to brew past the point at which the pioneering species are required (i.e. A long batch brew) will surely lose those pioneering species and become dominated by later stage fermentation species.

    Is that not so?

    I hear what you are saying that your continuous brews turn vinegary, but this cannot be the explanation, because the opposite is logically true.

    Or what am I missing?!

    Thanks :)

  • Eric Childs
    Eric Childs

    Hi Sam,
    Sorry to hear about the mold but it happens. Dont fret it. Were you using the same SCOBY each time over the last 7 years?? Best way to keep a full spectrum highly active SCOBY is using the newly formed SCOBY on the surface along with fresh starter liquid. If you have been doing that the most common cause for mold is temperature if below 68F. Also improper acidification. If you have a PH meter make sure your sweet tea is at a PH of 3.6-3.8 at the start of fermentation. This will ensure no mold will form if you have an active culture. Hit us up on email if you have any more follow up questions and Happy brewing!
    Come visit us in Kingston!

  • Sam
    Sam

    Thanks so much for all the tips on this site as well as this helpful article reaffirming my batch brew method. I’m a homebrew beer guy, who always keeps a batch of buch on the side, cuz it’s so darn easy and so damn tasty in the morning back sweetened with some tropical fruit medley… anyway, I just had my first mold infection on a 4 gallon batch I’ve had going for over 7 YEARS! I know you warn against anthropomorphizing your SCOBY, but I am still in mourning since this morning, and wondering what I did wrong or differently this time around. I think I must have left a finished batches sitting through past winters in a sort of “hibernation” and making a new batch in the middle of winter this year did not bode well for the culture, which left the door open for some errant mold to take hold. aaanyway, I’m taking this all as a learning experience as I plan start completely over with a brand new batch this weekend after the New York City Fermentation Festival. Hope to see you there.

  • Utku
    Utku

    Can I using only sugared water to make kombucha without tea? I wonder that can bacterias grow without tea?

  • Becky
    Becky

    Doesn’t putting the scoby hotel in the fridge promote mold?
    Is this just old information ?

  • Yu
    Yu

    I am a newbie and started in Dec. We love it and want to make more and I started researching on continuous brew and found your article…
    My question now is about the SCOBY hotel, if I have some stored in a jar at room temperature for less than 2 months, are they still good SCOBY if I now put them in the fridge now? And will I need to “air out” from time to time with a lid on? Thanks!

  • cynthia swinimer
    cynthia swinimer

    I have a question on the scobys.
    I added 16 c if sweet tea to about 4 cups of brew after I bottle off my KT.

    I left all the scobys in the bottle.
    From your comments I now know next time to take out all the old scobys and only leave the newest top on for the new brew.
    Is this all correct?

    What do I do with the old scobys? Do I add them to a hotel?
    If so will they get too old as you noted only to use new babies for the new brew .

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