1. Homebrew Souring
A brief primer

2. 1 2 3 4 5 Agenda Kettle Sour Cooler Sour Sour Mash
Fermentation Souring 4
Spontaneous Fermentation 5
Agenda

3. Kettle sour Mash, sparge, and collect wort 2 options
Pitch lactobacillus, sour, then boil
Boil then pitch Lactobacillus
SBB best practices
Sour then boil – drop ph to 4.5 with food grade lactic or phosphoric acid
Boil then sour – less than 10 IBUs and after boil reduce ph
Cool mash to under 120 degrees
Add pure lactobacillus or unmashed base grain
Remove o2 and seal as best you can
Maintain 112 – 120 degrees, if possible
Monitor ph until desired level
~3.6 typical Berliner weisse and gose
~3.3 strongly sour
~3.4 to 3.5 some saccharomyces may have trouble fermenting
Once desired ph hit, boil or transfer to fermentation vessel

4. Cooler Sour Mash, sparge, gently boil wort Cool wort to ~100 degrees
Transfer to cooler
Pitch pure lactobacillus plantarum
Let temp free fall on its own
Monitor sour levels via taste / ph
Transfer to kettle and boil
I got the idea for this from a reddit post.

5. Sour Mash
Conduct typical mash, introduce lactobacillus, keep warm to desired sourness
SBB best practices
Reduce ph to 4.5 with food grade lactic or phosphoric acid
Mash out
Cool mash to under 120 degrees
Add pure lactobacillus or unmashed base grain
Remove o2 and seal as best you can
Maintain 112 – 120 degrees, if possible
Monitor ph until desired level
~3.6 typical Berliner weisse and gose
~3.3 strongly sour
~3.4 to 3.5 some saccharomyces may have trouble fermenting
Once desired ph hit, raise temp to 170 – 180 and spare as usual

6. Fermentation …

8. Spontaneous Fermentation
Allagash Brewing Koelschip
Spontaneous Fermentation

9. Spontaneous fermentation
Allow wort to cool in the open in order to “pick up” wild yeast and bacteria
Often put into reused barrels that house microbes from previous batches
Pro
It’s cool!
Don’t have to pay for yeast!
Cons
You get what you get … if you get anything at all
Very hard to impossible to replicate if you start from scratch for each batch

10. Resources / getting started
Check out the sites below for more information
Sour Beer blog - fermentation/
Mad Fermentationist - sour-beer-at-home.html
American sour beers by Michael tonsmeire