Tuesday, July 29, 2014

24 Hour Sour IPA (closed system kettle sour mash)

What if you could make a very sour beer using bacteria in 24 hours? Would you be interested in that?

One of the great things about home brewing is the ability to do whatever the hell you want. The cost of failure is practically nothing at this scale. Even if the beer ends in complete failure, the few dollars wasted on ingredients is well worth the knowledge gained. The beer brewed in the lab this past week falls squarely into the experimental (otherwise know as fuck it if it doesn't work) category.

Sour beers are all the rage these days. I have long been a fan of these beers but I do have a limit on sourness. More and more it seems some brewers have tried to take sourness to the extremes. To each their own, but sourness for the sake of sourness is not drinkable at all for me. I want to taste layers of flavors in my sour beers, not just sourness. 

I have done a few sour beers over the years. The big issue I have with brewing them is that many of the techniques either produce unpredictable results or take a very long time. These are things I have little patience for. One of the techniques I have used is making berliner weisse by pitching lacto and ale yeast. There are theories abound as to when to pitch the lacto and when to pitch the yeast. In my experience it is still always a crap shoot as to what you will end up with.

A friend and I have been thinking about doing a sour beer for some time now. To get around the issue of unpredictable pH and or long timelines we decided on a sour mash. Sour mashing is a technique where wort is soured pre boil, and then finished as you would with any other beer. This way you get an idea upfront on the level of sourness and it is very fast. The other thing to note with this method is that the beer will never really get any more sour over time.

Over the last few months we have refined the concept to try to keep the souring as clean as possible. What that meant was not doing the most traditional method in which wort is left in contact with grains in the mash tun. Sour mashing gone bad can result in many unpleasant vomit inducing smells.

The closed-system soured mash procedure

The first step is mashing and sparging as normal. Once all the wort makes it into the kettle a quick boil is in order. This was mainly done so we could use the boiling wort to sanitize the plate chiller we used to cool the wort down. This could also be beneficial for killing anything that made it through the mash process. However you could simply let your wort chill on its own to ~120 degrees and probably still be fine.

The next step is to move the wort it into a 15.5 gallon sankey keg (you could use a corny keg as well). The idea/benefit around moving to this vessel is that you can purge all oxygen. The nasty bugs that are possibly going to make your sour mash smell and taste terrible all need oxygen. Luckily our Lacto doesn't need that.

There are a number of ways to inoculate the wort. One is to add some crushed grain. It's cheap, but it is also somewhat unknown as to what all is on that grain besides the lacto. It may not matter much in this closed system, but you never know. Another fine option is to buy a lab produced lacto. Can't really go wrong there. However with this beer we used plain yogurt to introduce the souring bacteria we needed. I went with a brand called Siggi's as it had multiple cultures including the delbrueckii strain.

At this point you have a keg filled with wort that is ideally around 110 - 120 degrees and ready for your bug pitch. After pitching the keg is purged with co2. An hour or so into the process pressure was beginning to build again so released it and placed an airlock on the keg (Remove your gas in post and place a short piece of 1/2 inch silicone tubing on it with an airlock) This is the closed system. It took only 24 hours for the pH to drop to 3.1. The other great thing is that the wort had no strange smells or flavors. It tasted like a pilsner lemonade since the wort was sour, but also still sweet.

The last step is to finish the boil. This will also kill off all of the bacteria. When using yogurt some extra filtering is needed. The yogurt seemed to curdle so in order to keep those solids out of the kettle I threw some cheese cloth into a strainer and drained the wort through the strainer. From there a 90 minute boil was kicked off.
The eDrometer reading

Hot break

This method can be used for any style of sour beer. This version happens to be designed as an sour IPA. A sour IPA would not be possible without utilizing some sort of sour mash, or adding lactic acid after fermentation completes. This is because Lactobacillus cannot handle hop levels much over 10 IBUs. Most people would say bitterness and sourness are a bad combination. Maybe it will be terrible, but I have had a sour IPA from Trinity Brewing called Red Swing line that was amazing. This is an attempt at brewing something similar but is not in any way a clone of that beer.

One other issue you will need to consider when pre souring is the fermentation. The low pH is going to be stressful to the yeast. The lower the pH, the harder the time the yeast will have. You should still be able to use ale yeast into the mid 3's, but you will want to use a very large and healthy pitch. The other option, and the one I went with is to use brettanomyces. It has some additional tolerance when it comes to pH levels.

Update: After some adding this beer turned out to be great! It will be brewed again!

1 comment:

  1. Where did you acquire the attachment to your keg that allows for an air lock as well as pressure and pressure release valve?