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Brewer’s Perspective: Brewing Gose with Brick West
Sam Milne of Brick West Brewing in Spokane, Washington, dishes details on their method of brewing kettle-soured beer—such as their Get Right gose, one of our picks for Best in Beer 2020.
So, you want to make a kettle sour, eh? This is truly one of my favorite styles to brew because, while the raw materials may be simple, executing this style to perfection is a challenge that requires absolute control of your process from start to finish.
pH Targets
For a kettle sour, pH is of obvious importance. I find it helpful to outline the various pH targets—throughout the course of the brew day, kettle-souring, and fermentation—to make sure I’m doing everything right to achieve those targets. Our pH targets are as follows:
- Mash: 5.5
- In the kettle, post-acid addition, pre-Lacto: 4.8
- Post-Lacto, pre-boil: 3.35
- Post-boil: 3.4 (pH tends to rise during a 90-minute boil)
- Post-fermentation: 3.3
Post-Lacto, we begin checking pH about eight hours after pitching, and then hourly after that if it is not ready. Usually, the pH is in range eight to 10 hours after pitching, but for certain strains, it may take up to 48 hours to complete acidification.
Purging Oxygen
Besides meeting pH targets, making absolutely certain that all oxygen has been purged from the souring vessel and eliminated from the wort itself is paramount to success. Any oxygen left in solution will result in butyric aromas (rancid, cheesy, vomit) in the final product, creating a beer that does not exhibit wonderfully bright lactic and lemony aromas.
So, you want to make a kettle sour, eh? This is truly one of my favorite styles to brew because, while the raw materials may be simple, executing this style to perfection is a challenge that requires absolute control of your process from start to finish.
pH Targets
For a kettle sour, pH is of obvious importance. I find it helpful to outline the various pH targets—throughout the course of the brew day, kettle-souring, and fermentation—to make sure I’m doing everything right to achieve those targets. Our pH targets are as follows:
- Mash: 5.5
- In the kettle, post-acid addition, pre-Lacto: 4.8
- Post-Lacto, pre-boil: 3.35
- Post-boil: 3.4 (pH tends to rise during a 90-minute boil)
- Post-fermentation: 3.3
Post-Lacto, we begin checking pH about eight hours after pitching, and then hourly after that if it is not ready. Usually, the pH is in range eight to 10 hours after pitching, but for certain strains, it may take up to 48 hours to complete acidification.
Purging Oxygen
Besides meeting pH targets, making absolutely certain that all oxygen has been purged from the souring vessel and eliminated from the wort itself is paramount to success. Any oxygen left in solution will result in butyric aromas (rancid, cheesy, vomit) in the final product, creating a beer that does not exhibit wonderfully bright lactic and lemony aromas.
[PAYWALL]
After a short five-minute boil to help scrub out any oxygen, we recirculate the wort through our cleaned, sanitized, and purged plate heat-exchanger (chiller), to cool it to a Lactobacillus pitch temperature of about 95°F (35°C). As we cool through the heat-exchanger, we also recirculate wort through the whirlpool inlet, to homogenize the temperature and prevent any stratification that could present a false reading.
Pay close attention to the proper temperature for Lacto introduction, as each strain has a preferred range. During this cool-down phase, we bubble CO2 through the carbonation stone at the heat-exchanger outlet as well as blanket the top of the kettle to further purge any oxygen that may be in the headspace. Once we reach the temperature and pitch the Lacto, we reduce the pressure of the CO2 headspace purge to about 1 psi, leaving it active until souring is complete.
Ingredients
In terms of raw materials, I like to stay stylistically accurate: German malts and hops for German-style beer. For water, we start with a relatively low level of total dissolved solids (TDS), knowing that we will add salt to the boil and a small amount of calcium chloride to the mash.
As for the salt and coriander, this really comes down to personal preference, but I’ve always erred on the side of “less is more.” To me, these ingredients are meant to be more of a layered intricacy and should never detract from the lactic flavors and aromas—only heighten them.
The specific Lacto strain is also a matter of preference; I have tried everything from Nancy’s Yogurt to Lallelemand’s dried Lacto to GoodBelly drinks before finally settling on the Omega Yeast Labs blend. We target a Lacto pitch rate of 10 million cells/ml (or about 190 billion cells for a five-gallon/19-liter batch), pitching at 95°F (35°C).
For primary yeast, I have always used a Kölsch strain for its acid tolerance, fermenting slightly cooler than usual to maintain a cleaner and more neutral fermentation. It’s all about letting the Lacto shine, and any fruity esters derived from fermentation will change the final product (for better or worse).
Finishing & Serving
For carbonation, we begin spunding when fermentation is about 1.5°P from FG (at about 1.014), allowing the pressure to reach 1 bar. This results in a final product with 2.7–3 volumes of CO2, achieved naturally.
Once the beer has passed the VDK test on two consecutive days (see “Hunting for Diacetyl,” beerandbrewing.com), we treat it similarly to our lagers, slowly reducing the temperature over several days until we reach our desired lagering temperature of 30°F (-1° C). Typically, we hold the beer there for a short maturation period of five to 10 days before packaging directly from the finishing vessel.
The last step is the most important—drinking! In my opinion, this beer benefits greatly from being served in a tall weizen glass or any other tallish glassware.
Ahhh, that was a lot of work. Let’s take a minute to enjoy our creation. Prost!
