Sour mashing

I wrote this up for our club's monthly newsletter "tech corner".

 

I live in a very warm part of the country and sour mashing that results in something that tastes good is very difficult without growing up a wild culture

What Ive done is do a starter with grain thrown in and then step this up once or twice. I do this becuase the bacteria that give nasty vomit/hot garbage aromas and flavors to the beer are easily killed off by a drop in pH. I do this in a starter because even small amounts that make it into the mash will never really go away, even through boiling and a vigorous fermenation. By making a starter that you step up your assuring that youve killed off the coliform/fecal bacteria and have yeast/lactic bacteria left

I should also note that its not as imperative to keep temps up going this route either. Start warm and if it drops so be it

 

I sour my wort, I don't do a sour mash.

My process which I've tried 5-6 times is as follows:

Once I drained my wort from my mash tun I put it into a bucket that I bought specifically for this lacto purpose. After it is cooled to 110F, I threw in a handful of grain (grain naturally carries lacto on it) and then put an airlock and lid on the bucket and put it in my fridge that I normally use for fermenting. I had put a light bulb in which I turned on and used as a heating source and it was kept insulated by the fridge, essentially creating an incubator. I maintained the fridge as close to 110F as possible because that is around the highest temperature that lacto likes to do its work without being killed (which occurs around 120F). As the wort began souring it gave off a creamed corn smell and when I took a sample it had a nice puckering sour. I was going for a big punch-you-in-the-mouth flavor so I soured it for 4 days.

I've tried variations of this method with these results:

4 days souring at 110F - way too sour, warhead level puckering, not desirable
4 days souring at 110F then blended 50/50 with fresh wort = perfect level of puckering tartness
6 days room temp 70F - lightly sour, gravity dropped drastically with minimal ABV contribution.
5 days room temp 70F with boiling water infusion 2x/day - slightly more sour, minimal off flavors, nice sourness and minimal gravity drop

 

I was listening to Chad Yakobson on Brewing Network the other day and he was saying that he drops his mash pH to 4.5 using Acid Malt to stave off the nasty bacteria. Then he goes through a sour mash.

 

So have you tried the souring at 110F for, say, 2 - 3 days? How would that turn out?

 

I asked a local brewery how they made their berliner weisse and they said they soured their wort as well rather than a sour mash. Two of the brewers said when they made their homebrew berliner weisses they soured their wort as well but taste it after two days. They made one and let it sour for 3 and said the wort was disgusting and dumped it. I'm sure results may differ but next time I make one this is the way I'll try to get sourness.

 

I've soured half of a batch for 4 days at 110F and blended with the unsoured half and it was perfect. So I'd guess the sweet spot is 2ish days.

 

Keep wort temp high (around 120) to suppress Clostridium growth while promoting Lactobacillus growth. Also flush mash vessel WELL with CO2, again this suppresses Clostridium sp & promotes Lactobacillum. THE WORT SHOULD NOT HAVE OFF AROMAS. IF IT SMELLS LIKE SHIT SOMETHING IS WRONG.

 

higher temps (120 = nearly ideal growth temp) wont suppress clostridium/enteric bacteria, actually quite the opposite as it will make anything and everything grow faster, same thing with a co2 blanket, it doesnt really actually do much of anything.

ONLY way to make sure neither are a problem is by acidifying the wort (like yakobsen) or doing a stepped up starter of the wild culture from the grain

making a starter of the wild culture also lets you feel it out and see both how sour it will get and if there are any strange flavors. Basically its a cheap way to proof the bugs/yeast your adding to your wort before you blow a whole batch

 

Is your lightbulb in the fridge the only heat source you are using to keep the fridge around 110?

 

Yeah the fridge is turned off and I found that the light won't make the chamber get over 110F being left on all the time

 

Interesting.

I'm gonna brew a sour sometime around Feb, so I can have it when the heat starts to roll in, and be able to have it on tap.

I might have to look into this. I hate the vomit like smell from it.

 

So essentially, you do a no boil? Drain it, sour it.. So it's much like a sour mash, minus it not being on the grain bed.

 

Sour or Berliner?