Sour Mashing (Declassified)
Posted: Wed Oct 14, 2015 7:49 pm
Here's a riddle... Ideal mash pH is 5.4-5.6, ideal boil pH is 5.2-5.4. Sparging raises pH, and by the Reinheitsgebot, German brewers aren't allowed to add acid to their beers. So how do they get to the ideal boil pH?
The answer is sour malt and/or sour wort. Sour mash can be added before lautering, and sour wort would have to be used for any necessary kettle adjustments. I don't think they're dropping the pH until after sparging is complete, the reason being that the sparge can release additional starch, and alpha-amylase is needed to convert this starch before it makes it into the kettle; the alpha would be inhibited by the low pH if it was lowered before sparging, hence the necessity of adding soured wort to the kettle, in addition to the sour mash used during mashing.
I, like most other homebrewers, use lactic acid to control my brewing pH; lactic acid has it's own distinct flavor, but a fermentation by lactobaccillus in a sour mash is going to produce a whole lot more byproducts and flavors than purified food-grade lactic acid...
I started thinking about other foods that use bacterial fermentation for acid production; sourdough bread, yogurt, and cheese all come to mind. Again, there's a whole lot more going on in these than the one-trick pony of lactic acid.
As far as beers go, Belgian lambics that use a slow cooling process and spontaneous fermentation most likely have a good amount of lactobaccillus fermentation going on in the initial cooling period before they are transferred to the fermentors. Lambics can have a hard-to-describe mineral/citrus/floral character that is not entirely unlike what we refer to as "IT" in continental lagers. Speaking of German beers...
The only German sour beer I have ever tried was Professor Fritz Briem 1809 Berliner Weisse. I only had it once, and it was a while back, but I remember thinking it had a character similar to a Bavarian Weisse, but with the additional sourness and funk added by the other bacteria. It certainly tasted like an authentic German beer, though.
I'm going to experiment with sour mashing and souring wort. I already have a cellar full of fermenting sour beers, so I'm not worried about contaminating any of my equipment with wild yeast and bacteria.
I found a little snippet about how commercial breweries are making there saurgut here: If I'm reading this right, they have a continuous sour fermentation going, and then draw wort off from this to use to adjust pH during mashing. I could do this by just keeping a lactobacillus-only fermentation going in a small glass jug; I know some strains of lacto are sensitive to hop bitterness, but hopefully I can get a strain going that is robust enough to sour extra wort I have left over from each brew session, otherwise I'll have to make special un-hopped wort to feed the culture, or feed it with pre-boil wort from each brew.
Anyway, I'm going to attempt it, and see if it adds anything. This method seems like much less of a pain than making a little sour mash several days before each brew session.
The answer is sour malt and/or sour wort. Sour mash can be added before lautering, and sour wort would have to be used for any necessary kettle adjustments. I don't think they're dropping the pH until after sparging is complete, the reason being that the sparge can release additional starch, and alpha-amylase is needed to convert this starch before it makes it into the kettle; the alpha would be inhibited by the low pH if it was lowered before sparging, hence the necessity of adding soured wort to the kettle, in addition to the sour mash used during mashing.
I, like most other homebrewers, use lactic acid to control my brewing pH; lactic acid has it's own distinct flavor, but a fermentation by lactobaccillus in a sour mash is going to produce a whole lot more byproducts and flavors than purified food-grade lactic acid...
I started thinking about other foods that use bacterial fermentation for acid production; sourdough bread, yogurt, and cheese all come to mind. Again, there's a whole lot more going on in these than the one-trick pony of lactic acid.
As far as beers go, Belgian lambics that use a slow cooling process and spontaneous fermentation most likely have a good amount of lactobaccillus fermentation going on in the initial cooling period before they are transferred to the fermentors. Lambics can have a hard-to-describe mineral/citrus/floral character that is not entirely unlike what we refer to as "IT" in continental lagers. Speaking of German beers...
The only German sour beer I have ever tried was Professor Fritz Briem 1809 Berliner Weisse. I only had it once, and it was a while back, but I remember thinking it had a character similar to a Bavarian Weisse, but with the additional sourness and funk added by the other bacteria. It certainly tasted like an authentic German beer, though.
I'm going to experiment with sour mashing and souring wort. I already have a cellar full of fermenting sour beers, so I'm not worried about contaminating any of my equipment with wild yeast and bacteria.
I found a little snippet about how commercial breweries are making there saurgut here: If I'm reading this right, they have a continuous sour fermentation going, and then draw wort off from this to use to adjust pH during mashing. I could do this by just keeping a lactobacillus-only fermentation going in a small glass jug; I know some strains of lacto are sensitive to hop bitterness, but hopefully I can get a strain going that is robust enough to sour extra wort I have left over from each brew session, otherwise I'll have to make special un-hopped wort to feed the culture, or feed it with pre-boil wort from each brew.
Anyway, I'm going to attempt it, and see if it adds anything. This method seems like much less of a pain than making a little sour mash several days before each brew session.