Brew Day: Salty Dog Gose
I have been itching to bring in some critters into my brewery that weren’t saccharomyces for a little while. I’ve been making a bit of research and finally decided to jump right in. I think a Gose (or a Berliner Weisse for that matter) are a great way to start this journey, because it does not require long aging periods, and with hot side souring, it can reduce the chance of infecting brewery equipment with bacteria.
For this beer, I did what’s called Kettle Souring or Sour Wort (?). The process is fairly straightforward. It involves mashing as you usually would, chilling wort to a range appropriate for your lactobacillus cultures, pitching lactobacillus, and holding the temperature for a few days. Then, you may or may not boil this wort, chill again as usual and pitch saccharomyces.
Lactobacillus eats up sugars and produce lactic acid which in turn lowers the solution’s pH. When souring wort, having a pH meter is important as it will tell you when to stop. If it drops too low, then saccharomyces will be inhibited, and if it’s too high, then it won’t be sour. Tasting the wort as you measure pH is good advice as well - you’ll know how it’s progressing and when it’s just too much, although when it’s carbonated it will be perceived as less sour.
A characteristic of Goses is that they do not have any IBUs. I didn’t add any hops at all, except for a few in the mash just for fun. But it’s notable that in general hops will inhibit lactobacillus activity, again, depending on species, so generally these beers have very little hops if at all.
For this time around, I am trying to go as simple as possible to get a feel for the process. I did some research on the style, and ended up with the following recipe:
Water chemistry was not something I found a lot of good information about. Because this is a very light-colored beer, I started off with RO water. But I didn’t think it’d be wise to go with completely soft water either, and it’s not a hoppy beer so I don’t need a high sulfate to chloride ratio. I just added a quarter tsp of both Calcium Chloride and Gypsum in my strike water. Along with a little bit of acidulated malt that I included in the grist, this should bring my mash pH to appropriate conversion levels.
Unfortunately, my pH meter broke down on brew day, so I was unable to measure mash pH, nor wort starting pH prior to pitching lactobacillus. I’ll just have to measure these on my next Gose.
|Weyermann Wheat Malt||5 lb||47.6 %|
|Weyermann Pilsener Malt||4 lb 8 oz||42.9 %|
|Melanoidin Malt||4 oz||2.4 %|
|Acidulated Malt||4 oz||2.4 %|
|Rice Hulls||8 oz||4.8 %|
Three fresh chinook hops from your garden in the mash (optional) :)
|Whirlfloc||1 tablet||15m left in boil|
|Yeast Nutrient||¼ teaspoon||15m left in boil|
|Crushed Coriander||1 oz||15m left in boil|
|Maldon Sea Salt Flakes||14 grams||15m left in boil|
|GB110 Fast Souring Lacto||GigaYeast||15%||1 bag in 2 liter starter|
|WLP029 German Ale/Kölsch||White Labs||78%||1 vial in 1.8 liter starter|
July 26, 2015
Built a starter inoculate with the lactobacillus package. I made it 2 full liters. Chilled it to 95F. After pitching the package, the Erlenmeyer flask filled pretty much to the top, which was the goal as to avoid any oxygen between the wort and the bung. Placed an airlock and sealed it by wrapping around with cling wrap.
July 30, 2015
Mashed in at 148F. Added calcium chloride and gypsum additions. Sparged and boiled for 15 minutes to help volatalize DMS from the pilsener malt.
During the boil, I quickly cleaned up my plastic cooler/mash tun to be used during wort souring to aid in maintaining an appropriate temperature.
Chilled wort using plate chiller straight into cooler, targeting 99-100F. It wasn’t easy to get this temperature, but by controlling the flow of water it got it down.
SG reading was 1.047.
Pitched entire lactobacillus starter into wort. After pitching, temperature was 98F.
Purged oxygen with CO2, closed down the cooler, and placed in warmest place possible. Ideally you’d control temperature and maintain it at 98F, which I don’t have equipment to do yet.
July 30, 2015
20 hours later, pH dropped to 3.5 and temperature dropped to 87F. I know it’s called “Fast Souring Lacto” but this seems very fast! Probably also due to the fact that RO water was used, and I didn’t add any bicarbonates, so alkalinity on this water is definitely low.
Built a started with one vial of WLP029 and yeast nutrients.
Aug 1, 2015
pH dropped to 3.3 and temperature to 80F. It’s definitely time to stop lactobacillus activity, which I did by boiling the wort.
Wort tasted nice and sour, but very clean. Getting pumped!
I crushed the coriander seeds by placing them in a bag and using a kitchen roller.
During the boil I added a Whirfloc tablet, yeast nutrients, coriander and salt
After boiling it, chilled as usual, aerated, and pitched WLP029 starter.
SG reading was 1.023, so this lacto did attenuate the wort a bit.
Aug 13, 2015
Racked off of primary onto secondary. Wort was very clear. SG was 1.011.
Sept 2, 2015
Kegged and carbed.
What I’d do differently
- For the lactobacillus starter, there are experiments which show using a bit of apple juice yield a more appropriate environment for lacto. Further, I’ll add some yeast nutrients which I didn’t do this time.
- I’d do more research on appropriate water profile, although it seems to me chloride and sulfate won’t play a big role in a sour beer like this. I might consider simply using acidulated malt and phophoric acid to tune in on an appropriate mash pH.
- I boiled for a full 60 minutes, but I don’t see any reason to having done that. Next time, a 15 minute wort with the remaining ingredients might be enough.
- I’ll add “test pH meter” to my pre-brewing flight check.
- Bring the wort pH down to 4.5 before pitching lacto helps with head retention, so give that a shot as well.