I want to make a starter for a kettle soured beer with a pure culture of Lactobacillus, but I want to able to keep some of the starter aside so that I can use it in future batches. If I were to use most of the starter and pitch it in the kettle soured beer, can I expect the stuff that is left behind to be safe to use in a month? What if I feed it some starter wort occasionally? There shouldn’t really be any alcohol in there to protect the wort from unwanted contaminants/pathogens, only a low pH.
Yes. The starter to keep will be protected by the lactic acid and low pH. It may also have some alcohol depending on the lacto strain.
Are you making sauergut ?
I’m assuming OP is making a quick-soured American Sour Ale.
I should have expounded more, since you basically are making sauergut. A pure strain can be used, as can most of the probiotic supplements, but some of the best lacto is naturally occurring on the grain.
Lacto like warm temps ~48c, you will certainly want to hold and maintain that until you reach your maximum acid level which will be 1.8-2.2%. Holding that temp will also kill any other yeasts that you don’t want. Its as simple as making some starter wort, and throwing a handful of uncrushed grain on top. Hold at 48c for 3-5 days, the grain will sink and you can just pour the gut off the grains. You could easily make 2l use 1l and put the remaining 1l in a sealed mason jar in the fridge for later. Your acid % with this method will be about 1.25%, but its easy enough to titrate and figure it out for sure.
Yeast survive at that temperature. They don’t reproduce well above 100-105F but cells do not die. Once the wort cools in the fridge the yeast will resume reproducing and fermentation.
[quote]Its as simple as making some starter wort, and throwing a handful of uncrushed grain on top. Hold at 48c for 3-5 days, the grain will sink and you can just pour the gut off the grains. You could easily make 2l use 1l and put the remaining 1l in a sealed mason jar in the fridge for later. Your acid % with this method will be about 1.25%, but its easy enough to titrate and figure it out for sure.
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This is a fine process for what you are doing because you use such a small amount of soured wort in a batch; however, it is a bad beer waiting to happen at a larger scale. Using luck of the draw to culture off grain increases the probability of off flavors in the beer because the volume of off flavor compounds is far greater in a full batch soured in this method over five percent or less that you use. That’s not to say one cannot ever get a good sour beer out of this process but the probability is not great. That’s why most brewers kettle souring use selected lactobacillus strains.
This is a fine process for what you are doing because you use such a small amount of soured wort in a batch; however, it is a bad beer waiting to happen at a larger scale. Using luck of the draw to culture off grain increases the probability of off flavors in the beer because the volume of off flavor compounds is far greater in a full batch soured in this method over five percent or less that you use. That’s not to say one cannot ever get a good sour beer out of this process but the probability is not great. That’s why most brewers kettle souring use selected lactobacillus strains.
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Which is why I store my culture at 48C forever for sure. Hrmm, I have a beautifully soured 5 gallon keg of sauergut, which I am sure would make a great batch of something like berliner. I used the methods outlined here;
http://www.lowoxygenbrewing.com/ingredients/a-sauergut-reactor/
Admittedly I am not trying to make a sour beer, but I guess I am. But yea sauergut is my specialty, not sour beers, so I will go away now.
OP here.
I already have the Omega Lactobacillus pack that I plan to use for a Berliner weisse type beer. My plan is to grow up a starter so that I can save some of it and be able to reuse it in the future for more of the same type of beer. It sounds like I am safe with just the low pH.
Since I am kettle souring then boiling, I won’t really be able to harvest the lacto from the kettle - they will have sacrificed themselves for the good of the beer, and the cleanliness of the equipment.
I have heard that the handful of grain can work for this type of beer, but I would rather have a little more control over the process at this point. I know the pure strain works well, and is less likely to have a beer taste like poop or vomit.
The sauergut explanation on the Low oxygen website is pretty interesting. Hard to believe it is capable of so many different things throughout the brewing process. I might give a couple of those steps a try, although I rarely make lagers.
For Sure!
Although they use it on every beer not just lagers! They refer to it as biological acidification.
That is not my finding. When properly acidified to under 4.5 and kept anaerobic, the potential to develop off-flavored or spoiling organisms is exceedingly small. In addition, when creating a starter culture this way, you have the ultimate QC equipment in the form of your nose and palate to check the result prior to use.
And the risk of having some yeast or other organism in your soured wort is also not a concern if you are using this wort in typical pre-boil settings. That soured wort will be fully sterilized via the boil.
My experience with pure lacto strains is that they have narrow flavor profiles that are not pleasing in finished beers. Using the handful of grain inoculation is an effective way to create a flavorful and safe starter.
I agree with all of this, with the qualification that I think the added depth of flavor from a grain-innoculated sour ferment is likely coming from other microbes other than solely lactobacillus. The amount of CO2 production that I have gotten using a handful of Pils malt as my innoculant is a lot greater than I’d expect from a pure lacto ferment. That said, that’s not a particular concern if you’re going to boil your sour wort anyways.
I have to agree with Martin on this. I’ve also noticed that my best sours are usually aged for a long, long time.
How long is a long time? I have a Flanders Red using Roselare Blend that is 12 months in the carboy. I am on the fence on whether to go ahead and bottle, kettle sour a new brew and blend, or just let it sit.
-Tony
If you grow the culture up several times it shouldn’t take too long to sour. I grew bottle dregs up several times in a flask and the beer I made was really sour in 7 months. That reminds me that I need to feed the culture today.