Remedial Brewing... serendipitious infection

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Remedial Brewing... serendipitious infection

I don't know how prolific the other brewers here are, but I probably fall near the top as a home brewer. I brewed all grain batch # 119 in slightly under 2 years tonight. More than a brew a week average. What I do know is that things occasionally go wrong, unless Murphy stays away from you. More often than not, it's mistakes and brain farts, and you have nobody to blame but yourself. What can go wrong, will go wrong, at the worst possible moment. My 78 minute no boil / no chill brew fell victim to one of these "Murphy incidents". I pitched fresh top crop from an adjacent fermenter, which as it turned out had a lacto infection I had not yet detected. There was no pellicle, no indication whatever that I had a problem, and that brew, tasted from the spigot appeared fine at that point. At a later date I discovered it was sour, actually a rather nice lacto sour, though an unintended wild sour. I'm NOT squeamish about wild sours, having brewed things like kombucha and kefir, which are both basically open cultures. I don't believe many if any organisms that can survive in beer are harmful to humans.
The remedy in this case was to monitor the brew, which was a very pale cream ale, and was already into secondary and not yet exhibiting sourness. This was a slow growing culture. I monitored it daily. I started detecting slight sourness at about day 11, and at day 13, it was perfect, so I decided to "freeze it" there. I then racked into my large stainless steel pressure cooker, and pasteurized it at about 170F, heating it to that temp and letting it slow cool.
The result........... a lovely if unintended "sour cream ale" which exhibits a distinctive "shandy" character, as this bug throws a distinctive citrus flavor. It's subtle enough that you could mistake it for something originating from the hops, and in fact a couple of people who have tasted it asked me what hops I used.
I'm NOT interested in repeating the process........the pressure cooker not something I want to use in brewing, nor do I want sours in my fermenters. I'm doing my damnedest to eradicate this bug, and expect to get it done, as the offending fermenters are currently submerged completely in starsan and will remain that way for a week.......fresh starsan. Spigots are disassembled and submerged also.
Now here is the problem........ I absolutely love the product. Other than the slight chill haze, which effects appearance slightly, it's one of the best light bodied summer type beers I've ever brewed. It has that distinct shandy flavor that nobody who didn't have experience with lacto sours would identify as being a lacto. A few days more, and it would not have been subtle. It is by far the best sour I've ever brewed. I was tempted to keep the culture, and probably should have to use as an innoculant for sour mash or kettle sour, but it's a very slow acting bug.

The challenge now is to try to figure out how to control a sour mash to achieve the same effect.... without blending. In the past, I've blended to achieve the results I wanted with sours. The batteries in my PH meter are dead, and I don't have any LR44 batteries. I'm tempted instead to get some antifreeze PH test strips from the local auto parts store and see what kind of reading I get on this brew, then attempt a sour mash, stopping it at the same PH.

I really would like to duplicate my Serendipity Cream Ale Shandy ............. anybody have experience with controlling sour mash?


Siberian's picture
I wouldn't try to control the

I wouldn't try to control the sourness in the mash to be honest.  I prefer kettle souring because I think it's more controllable.  But, it's hard for me to make a specific recommendation how you'd do it without really knowing how your system works.  So, I'll just explain how I'd do it, I've done several kettle sours and have had great success without any off-flavors and without resorting to the use of CO2 on the kettle that some folks recommend.

I brew in a bag with a RIMS system, so I'd mash in as normal, run off and then immediately bring it up to a 10 minute boil to pasturize the wort and kill everything that was living in the grain.  I want to be sure the only thing growing in there is lacto, no funny stuff making butaric acid or something. Then I'll chill down to about 100 degrees and set the RIMS to recirculate and hold it there.   

For cultures, you have a choice at this point:

  • You can pitch a commercial (white labs/wyeast/etc) starter of lacto into the kettle now. 
  • You can pitch a starter of commercial lacto.
  • You can pitch a starter of wort that grew up lacto from Greek Yogurt with live cultures.
  • You can just throw 1/2 cup or so of greek yogurt right into the kettle.

I've done the last two, worked great on multiple kettle sours.  I've moved to just tossing the yogurt in directly, by the end you never know it's there. I brewed a kettle soured Gose that won a local club style competition that way

Now, additionally you'll want some good PH stripes or a meter and a bottle of lactic acid, you need to toss in enough acid to lower the PH to 4.5 (or lower, don't worry about hitting it on the nose) through pure acid additions, just to be safe and make sure nothing bad grows up along with your lacto.

Now, cover it with a blanket or however you would want to insulate it and let it ride for a few days, check the PH along the way until it gets where you want.   Don't check too often, the less you open the kettle the better, if you can pull your samples off a recirculation system or ball valve (I disconnect a hose and run a bit into a glass) that's better that opening the kettle.

At that point once your happy with the PH, bring it back up to a boil, hop if needed for your recipe, chill again, and pitch a BIG starter of your primary yeast.  I'd say at least 25-50% more then you'd normally pitch, the more recent/active the better.

This acidic of wort can be somewhat tough on the yeast, I've had pitches not take and had to resort to dry yeast as backup, so be sure to pitch a bit more then you might normally or a very active starter.

At that point though you'll have a lactic sour beer, with no infectious bacteria left alive.

Also, keep in mind in fermentation yeast will drop the PH a bit on their own, so you might find it finishes a little lower then expected if you run the wort all the way down to the same PH.   Also if you don't have this kind of temp control to hold the kettle at 100 for several days, keeping it just in a warm place is good enough, the lacto might just be slower.