Summers are for Sours

The (Not So) Basic guide to Sours

This summer is HOT! I’ve seen videos of car hoods cooking bacon, I’ve felt myself drown in brewery sweat, and the whole thought of summer has me feeling sour. Good news about the 110 degree weather we’ve been having; It’s the ideal temperature for making sour beers.

 

What makes beer sour?

 

Sour beer is beer that has been made acidic. It often tastes tart and, if crafted correctly, dynamic in flavor. It can be organically created by microorganisms or added artificially.

 

What is the difference between adding Acid to beer and Souring beer/wort?

 

Have you ever compared artificial flavoring and the real deal? It is very similar. Artificial acids, like citric acid, leave a sour flavor without a level of complexities behind it. We’ll get into Sour Beer Complexities later. Biologically generated wort is like creating several colonies of unique organisms to generate a masterpiece of left over… without getting too in depth and driving you away; It is much like Beer compared to ethanol and malt extract. There is a lot more to it than meets the eye.

 

Microorganisms that can make and break beer

Saccharomyces

We’ll start with yeast but we’ll be brief since it is key player in beer fermentation. They can contribute esters if treated appropriate and can come in many different varieties that lead to several flavor compounds relating from bananas to peach or butterscotch to vomit if you don’t know what you are doing. This isn’t the key player for this topic, however, very important.

Lactobacillus

Some brewers fear this guy. Other brewers learn how to harness its power and show it it’s place. This microbe is the sour milk bacteria. Yogurt, pickles, and sour dough are all by-products of lacto. It may be, other than Saccharomyces, my favorite microbe. It spits up lactic acid that contributes to the unique food’s flavor. It is relatively easy to kill and provided you have good sanitation practices it won’t be staying around unless you want it to. It also grows well at 110 (degrees) Fahrenheit but can’t withstand a good boil.

Pediococcus

It’s in the lactobacillaceae tree so it’s pretty similar to lacto. It produces lactic acid and aids in sauerkraut fermentation. It’s a big risk with diacetyl. It is also pretty dang easy to kill so no contamination worries about this one either.

Brettanomyces

If making sour beer was an Olympic relay I imagine this guy is the anchor and takes the gold each time. It gives off a barn yard flavor and aroma. It is also described as horse blanket. This guy is so tough it can eat wood sugars. (Hint: barrel aging with this guy is awesome) It is also near impossible to get rid of once you have brewed with Brett. I suggest using separate dedicated equipment when dealing with this one. I imagine after a great mass extinction, like a nuclear winter, it will be twinkies, cockroaches, and Brettanomyces hanging out until the end of time. Some strains have the mechanism to make acetic acid. We really don’t want our sour to turn vinegar.  The resilience of this organism is what really allows the sour beers to be made prior to fermentation. The pH is too low (it is super acidic) for some yeasts to really perform the way they normally would.

 

The above team add intermediate compounds of fermentation, and lactic acid. Those intermediate compounds give it the complexities that beat the just-adding-acid approach.

 

Ways to Sour

 

You can sour at any point in the brewing process; Mash, kettle, fermentation, and storage. I don’t really like souring beer I’ve already made so I don’t practice souring during fermentation and storage. You can get great results souring at those steps but my logic is this; “if I made beer that is good why would I make it go sour?” This means I sour before it is beer.

If you do a sour mash don’t sour the entire mash, save about 5% of your grist for souring then add the sour grains to the mash. Kettle souring is what I prefer. I actually use a fermentor for my kettle sour but I do it after the mash and before the boil so it’s a “kettle sour.” I go the natural root for souring and just add some non-mashed grist as my “pitch” but you can buy all sorts of microbes online. My method doesn’t always yield the same like a controlled pitch does, but hey, character. If you want a reproducible sour: buy and grow the microbes. Don’t forget to wait for your temp to drop to 110 before pitching. For all methods of souring it is pretty much the same;

 

1.     Get the pH of Your Wort/Mash Below 4.5

Add food grade lactic acid or whatever it takes because you want to inhibit the growth of organisms that don’t sour. If you don’t get your pH down, you could end up growing a soup of botulism or anthrax and that would suck.

2.     Make the Environment Anaerobic

Attach or get your CO2 (if you don’t keg beer yet and still bottle, get yourself kegs and CO2) at the bottom of your souring vessel and pump CO2 as long as you can tolerate. Overnight works if you want to keep the CO2 flow low and long or if that doesn’t work you can do higher flow for more than 10 minutes. CO2 is heavier than oxygen (O2) and will push it up and out of your vessel. Doing this scrubs out oxygen and acidifies your soon-to-be sour mixture. The scrubbing (removal) of oxygen is crucial! With oxygen other organisms grow, the organisms that you want to grow are not going to produce acidifying products, and it typically turns out putrid. Make sure to cover your vessel so oxygen does not fall back into your vessel.

3.     Find a Sanitary Way to Check the pH

I soak a long pipette in sanitizer to pull my samples. Monitoring pH is brewing may be more important than gravities. It is SOOO IMPORTANT. pH is the omnipresent and omniscient aspect of any aqueous solution. It is what well tell you if you are souring or not. I try to end before it gets to a pH of 3.3. After about 3.4 it gets too sour for yeast to ferment it. “Hello, is it me you’re looking for?” –Brett. It’s also crazy sour below 3.3.

4.     Keep it Warm!

Around 110 degrees Fahrenheit for souring or as close to that as you can get it. That was the whole point of this article. Hopefully summer has got you thinking sour too.