Wednesday, 8 July 2015

Choosing the Right Probiotics for Souring Beer

A more-and-more common practice for quick sour beers is to use probiotic pills as a source of lactobacilli for the souring process. Indeed, the Milk the Funk Wiki has a growing list of alternate sources for these bacteria, including many probiotic capsules. A question that seems to rise quite often on this topic is "can I use probiotic brand X for souring beer". So here is a quick guide on figuring out whether a probiotic will work for souring beer.

In general, probiotic organisms fall into four categories when considering using them for souring:
  1. Good choices
  2. Probably don't matter
  3. Avoid under some circumstances
  4. Avoid at all cost

Good Choices:

Bacteria that represent good choices are those which have the capacity to sour wort, and will do so with a minimal risk of off-flavours. These are solely species belonging to the Lactobacillus genus - i.e. Lactobacillus sp, where sp merely means "any species".  Lactobacillus plantarum and Lactobacillus rhamnosis are two of the more commonly seen probiotic strains, but any probiotic containing bacteria whose name starts with 'Lactobacillus' will work well.

Probably Don't Matter:

Species which "probably don't matter" are those which are unlikely to grow in wort; either because the homebrewer lacks the ability to lower the oxygen level in the wort to the point where these organisms grow, or because wort isn't nutritionally compatible with these species. The flip side is that if these organisms grow, they should do the same thing as Lactobacillus - i.e. sour the wort while producing minimal off-flavours. So that's why they probably don't matter - they're not likely to do anything, but if they do end up doing something, they will help your wort sour. Included among these are:
  1. Bifidobacteria sp. (again, sp means "any species")
  2. Streptococcus thermophilus
  3. Leuconostoc sp.

Avoid Under Some Circumstances:

Only one group of organisms fall into this grouping - the Saccharomyces, as in species of yeast from the same genus of yeast that brewing yeast come from. At the time of this post the only Saccharomyces commonly seen in probiotics is Saccharomyces boulardii. Saccharomyces sp. fall into the "avoid under some circumstances" category as they will ferment sugars to form alcohol. You probably should avoid these - they will compete with Lactobacillus for sugars, and thus limit acidification. In addition, if you are planning on heating the wort after souring (to either pasteurizing or boiling temperatures), you will boil off the resulting alcohol leading to a beer with very little sugar left for the subsequent fermentation.

So as a rule you will want to avoid these, although it may be an interesting experiment to see what kind of beer you get if you pitch a Saccharomyces boulardii-containing probiotic mix into your fermenter.

Avoid At All Cost:

The last group are those you want to keep as far away from your wort, beer and fermenter as possible. These are bacteria which can produce horrid off-flavours and ruin a beer. In this group there are currently three types used in probiotics, but this list may get longer in the future:
  1. Clostridium sp. These guys can make butyric acid, which smells and tastes of a mix of parmesan cheese and vomit.
  2. Enterococcus faecium. This bacteria can make bioactive amines, which some people are severely allergic to. Moreover, these amines are often quite unpleasant, and are what give shit and corpses (among other things) their unique odours.
  3. Bacillus sp. (most often Bacillus ereus, clausii, and pumilus) make diacetyl (butter) and may also make bioactive amines.
Clearly, we don't want t be dumping any of the above guys in our beer!

EDIT/UPDATE: Stefan Wiswedel has done some experiments looking at probiotics containing amylases (which break down starches/dextrans) and protinases (which degrade proteins) along side the usual probiotic bacteria. Turns out using these is a bad idea - it kills the body and flavour of the resulting beer. Stefan has posted additional details in the comment section, below.

A Simple Rule of Thumb

So that's a lot - but a good rule-of-thumb is to limit yourself to probiotics that contain only Lactobacillus species, which is easy to remember when you're at the store. 

But if your memory is better than mine, than any probiotic with Lactobacillus sp. plus any of Bifidobacteria sp.Streptococcus thermophilus or Leuconostoc sp. will be good as well.

And if the probiotic contains anything but the above 4 groups of organisms, I'd recommend you stay away.

27 comments:

  1. hey! i had problems using lactobacillus casei shirota from yakult when souring wort.
    the same problem as reported for L. delbrückii - pH stucks at 4.2

    just as a sidenote

    ReplyDelete
  2. Any recomendations on how to make a starter from probiotic capsules?

    ReplyDelete
    Replies
    1. Prep ~1L of 1.040 wort, boil to sterilize, and let cool to 40C or so. Throw in the capsule and keep at 40-45C for 24 or so hours.

      The other option though is simply to dump 4 or so capsules right into the wort. Saves you a day, not sure where you end up price-wise.

      Delete
  3. Replies
    1. Already covered in the 'Probably Doesn't Matter" section

      Delete
  4. Hey Bryan,
    Have you ever seen enzymes in probiotics? I've just bought some that have an amylase, three types of protease, a lipase and a glucoamylase. Will be interesting to see how they effect wort. Wondering if you've had any experience with this.

    ReplyDelete
    Replies
    1. I've not encountered that. I'd be worried about amylase and proteases, as these could alter the wort (breaking down dextrins and destroying head-retention/body-providing proteins)

      Delete
    2. Yup, I had the same concerns. I did a 500ml +-1.030 LME starter with the enzyme probiotic and one with only L. plantarum. Left them for a few days and pitched some yeast last night. Will see how they compare in a week or so.

      Delete
    3. In theory the enzymes should have a limited lifespan; perhaps the run through the starter was enough to kill the enzymes off.

      Please let me know how this goes - its always good to know if these theoretical risks translate into real-world problems or not.

      Delete
    4. Well, they are both fermenting away nicely. Only thing I've noticed so far is that the one with enzymes had almost no krausen while the one, without enzymes, had a healthy looking krausen. Might have to do with the proteases destroying head-retention proteins.

      I think I might just bottle and carbonate with carbonator cap in a few more days and see how each tastes.

      The experiment continues...

      Delete
    5. OK. So I put them both into plastic bottles with carbonation caps, carbed and tasted. The pure L. plantarum one tasted as expected. Unfortunately the LME I used was quite old so there is quite a lot of residual sweetness. But otherwise it was fairly tart and clean with reasonable head retention.

      The probiotic with enzymes was another matter. It tasted thin and watery. Had some nasty higher alcohols in aroma and flavour and head retention was non-existent. Still quite tart though.

      I would add enzymes to the avoid at all costs section ;)

      Delete
    6. Very interesting, thank you for the added information (and post is updated accordingly).

      Delete
  5. Hi, thanks for this write up covers all the info and wish I had read this before going ahead.
    The capsules I got contain colostrum powder, so does that fall under Clostridium sp. One thing to note is that next to that ingredient there was no cell count un like the lactic and bifid species.
    Cheers

    ReplyDelete
    Replies
    1. colostrum powder is a fancy word for dried milk; nothing to worry about

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  6. Hello. I know people use probiotics for fast souring but are they also good for aged sours?
    I am going to brew the Milk The Funk Berliner recipe but want to use a probiotic with the "brett" trois instead of a commercial culture. Would this work? The probiotic in question is sold refrigerated would this cause a difference in results? And how do you try and assure you get as close to drug grade capsules as possible to reduce infection risk?

    Best Regards

    ReplyDelete
    Replies
    1. The MtF berlinner is done in a pseudo-kettle sour format (but soured at room temp), so probiotics may work. I would try to keep it warmer - 35 to 44 C - to ensure proper souring. The advantage of the Omega blend is that it sours at cooler temps, which is one of the reasons the MtF berliner uses it. A refrigerated probiotic is better - it means the store knows how to preserve it properly. I just use the capsules straight (open them up and dump them in); they should be resonably clean.

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    2. So it would probably be better to get a white labs culture as that's what the lhbs has and pitch that. Then just save the yeast cake?

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  7. I would like to try kettle souring with kefir. The one i have on hand one has these microbes:

    lactobacillus acidophilus
    bifidobacterium
    streptococcus thermophilus
    lactococcus lactis
    leuconostoc mesenteroides

    any of these microbes are covered in your explanation except for the "lactococcus lactis", do you think it should be avoided or can i proceed this combo?

    ReplyDelete
    Replies
    1. sorry i mean "all of these microbes...."

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    2. I *think* it will be fine, although I cannot guarantee it. All of those are lactic acid bacteria. My only concern would be that some of them (e.g. the strep) may produce above-threshold butyrate, which may or maynot work in the beer.

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  8. another concern i've found about the strep is its notable proteolytic activity..another choice could this combo from a goat's milk yogurt:
    strep thermophilus
    lacto bulgaricus
    lacto paracasei
    lacto rhamnosus

    but the strep is always there..Final beer should be a "fake" oud bruin with a lacto head-start and then a pitch of both s04/us05 yeast.

    About the butyrate some fruity could fit in the style but if it's a lot above threshold what will come out it's anobody guess...

    ReplyDelete
  9. This bacterial strain is most commonly found in sauerkraut and kimchi. The variety is very resilient and it can survive the travel through the stomach and being subjected to the effects of gastric acid.

    Just like lactobacillus acidophilus, lactobacillus plantarum plays an important role in guaranteeing the integrity of the gut lining.

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  10. Thanks Bryan, this article is exactly what Ive been looking for. Great job.

    I'm brewing a Berliner Weiss and have an option between 2 possilbe probiotics. The first contains only lactobacillus plantarum and the second contains lactobacillus acidophilus, bifidobacterium lactis, lactobacillus casei and Lactococcus lactis

    Ive heard that single strains might be a bit one dimensional, so not sure about the first option. Regarding the second option, bifido shouldn't be an issue according to your article, but I have a concern about lactococus lactus, which is not mentioned.

    Do you have any views on this?

    thanks


    ReplyDelete
    Replies
    1. Whether or not you'll get more complexity out of the mix is somewhat of a crap-shoot. Most of the lactobacilli produce similar acid profiles, although other flavour characteristics (lemon, mineral, etc) are reputedly made more by some strains than others.

      Bfidio will, in all likelyhood die soon after adding it to wort - most Bfidio strains die when exposed to even low levels of oxygen.

      Not too sure what the lactococcus will do; they don't utilize many of the sugars present in wort (minimal fermentation of maltose, sucrose and maltriose), but can grow off the the glucose and fructose.

      Delete
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