Souring with Probiotics

Over the past five years or so the craft beer industry has experienced an exponential growth spurt like we haven’t seen before.  The evolution of the beer scene has caused not only consumers but brewers alike to constantly search for the next best beer. Whether it’s a specific style or a certain ingredient; the quest for the perfect beer wages forward even though this is undoubtedly an unattainable goal.  While that goal may never be achieved, there are styles of beer that are sought after more than their counterparts. As I’m writing this the most sought after style of beers are without a semblance of doubt: sours.

Sour beers are in such high demand that breweries and home brewers alike are trying to find the newest, quickest, and efficient ways to create them. Brewing a sour beer is normally a testament to patience, the average turnaround on a sour beer is normally 6-9 months. There are other ways to go about this (sour worting[i], sour mash[ii]) but those techniques are not foolproof and you can end up with a myriad of problems ranging from butyric acid (cheese), diacetyl (butter), or acetic acid (vinegar).

Let’s talk a bit about what makes a beer sour, the rod shaped bacteria is called “lactobacillus[iii].” In addition to beer, this bacterium is also used to ferment cheese, yogurt, and wine amongst many other products. In order to create a sour beer the pH of the wort (unfermented beer) must drop from the 5.2 – 5.7 area to 3.4 – 3.1. In order to do this you must keep the wort at a temperature between 90°F and 120°F for anywhere between 24-72 hours on average. There are many different strains of lactobacillus and the more strains you use per beer the more complex flavors you will get. Some strains will create sour apple flavors, some will create lemon, and others will create both and add depth to your beer.

Brewing with bacteria and other unpredictable organisms is a very delicate process and with many breweries offering sour programs upon startup they do not have time for batch inconsistencies or long turnaround times. That leads to the purpose of this article – a quick souring process that doesn’t possess a small margin for error. What I mean by this is; by simply following instructions you should be able to create a sour beer without running a risk for off flavors and smells. After joining the Facebook group “Milk the Funk[iv]” I was turned onto a method of souring using probiotics (Milk the Funk is a group of commercial and home-brewers that specialize in the use of alternative sources of yeast [bacteria, wild yeast]).  They recommend two different types of probiotics for their souring: Lawsons and Goodbelly[v]. I was able to acquire “Goodbelly pomegranate blackberry probiotic shot,” which is exactly what it sounds like; a probiotic drink flavored with pomegranate and blackberry. The group suggested mango, but I was unable to locate the mango flavor[vi].

After absorbing as much knowledge as I could possibly retain I felt I was ready to take the plunge into brewing this. I had once before brewed a sour, or attempted to brew a sour, but it was riddled with butyric acid and tasted more like an elote then it did a gose. Naturally I was a bit hesitant to brew this same style, but that is half the fun when it comes to brewing – understanding your failure and improving upon it.

Two days before the brew day I created a 1000ML starter with light DME[vii] with an OG[viii] of 1.040. I then brought it down to 95 degrees and pitched in two shots of the Goodbelly probiotic. The Goodbelly probiotic contains one strain of lactobacillus; plantarum. So while this won’t give the most complex tasting sour in the world, it will create a very light, lemony-tart tasting beer. Perfect for a style such as a gose[ix], which is very crisp, refreshing, and of course delicious. Once the lactobacillus was pitched I held the temperate for 48 hours at a constant 98°F. We will get back to that later, on to the brew itself.

The grain bill was very simple; 50% wheat and 50% pilsner malt was used to create this. It was mashed[x] for 60 minutes at 145°F. Once the mash concluded it was time to sparge[xi]. In total 5.1 gallons of wort was collected from the grain and it had an OG of 1.036. The wort was brought to a quick boil (15 minutes) and then an addition of .75 ounces of Sea Salt and 1.0 ounces of Coriander were added. Once the wort was transferred to a carboy[xii] it was cooled to 100°F and the lactobacillus starter that was created 48 hours beforehand was pitched[xiii]. I allowed the wort and bacteria to work together for 48 hours before I pitched in the saccharomyces[xiv].

A starter of White Labs 644[xv] was pitched after a 1000ML starter was made 24 hours prior. After two weeks the FG [xvi] stabilized at 1.006 and its final ABV percentage was 3.94%[xvii]. A sample was taken prior to bottling and it was a very accurate representation of what a traditional gose should taste like. We were very happy with the results, but it still needed to be bottled and naturally carbonated. We bottled 4 gallons and siphoned the extra gallon into a smaller carboy where it will rest on apricots for 2 weeks before bottling.

It has been roughly 11 days since we bottled and I opened up the first carbonated bottle and was blown away by the beer. It was everything you look for in a gose; it was noticeably wheaty with lemony-tart bite followed by a subtle salty finish. All in all, it tasted fantastic. As stated before, with just the one strain of lactobacillus used you aren’t going to get the most complex flavors, but you don’t always need that. This is straight forward and very refreshing, the perfect summer beer.

Overall I’m very satisfied (if you couldn’t tell) with the results from the Goodbelly probiotic (lactobacillus plantarum) and will definitely be using this method in the future. I already sourced the Mango version of the drink to see if it really does alter the flavor or aroma any less, because with the pomegranate blackberry there is not one discernible flavor or smell. We have already brewed a long term sour (that has been aging for about 4 months now), but when we want to create something quick and tasty this will absolutely be the go-to-method.


[vi] Mango was suggested because it has the least amount of an effect on taste and smell.
[vii] Dry Malt Extract
[viii] OG refers to Original Gravity – the depth and density of the wort pre-fermentation
[x] Mashing is the brewer's term for the hot water steeping process which hydrates the barley, activates the malt enzymes, and converts the grain starches into fermentable sugars. There are several key enzyme groups that take part in the conversion of the grain starches to sugars.
[xi] Sparging, also called lautering is a step at the end of the mashing process where hot water is run through the grain bed to extract any leftover fermentable sugars.
[xiii] Sour beers do not have to be boiled, when creating a traditional beer they must be boiled for a minimum of 60 minutes. No hops used in making this beer, also unique to sour beers.
[xiv] It is known as the brewer's yeast or baker's yeast. They are unicellular and saprophytic fungi. One example is Saccharomyces cerevisiae, which is used in making wine, bread, and beer.
[xvi] FG refers to Final Gravity – the depth and density of the wort post-fermentation
[xvii] ABV is calculated by this equation (OG – FG) * 131.25

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