WLP036 problems at cool temps

Ingredients
1

I’m a new AHA member and this is my first post in the forums.

I brewed a partial mash variation of Jamil’s Cowboy Altbier and pitched WLP036 Dusseldorf Alt with a starter on Oct 19th. I put it in my basement at what I thought was a stable air temperature of 64F.  My job requires that I travel and I came home to a 56F basement and carboy (The outdoor temperature took a nose-dive and so did my basement). It seems that all activity had stopped at 1.024. I brought it upstairs to a stable 66F and gave it a shake once it warmed up. There still seems to be no activity and the gravity is the same.

Questions if the gravity doesn’t progress:

  • Should I increase the temperature even more?
  • Should I re-pitch?
  • If so should I use WLP036 again or use something with more attenuation like US05 or maybe WLP029?
2

66-68F should be plenty warm if you get yeast back in suspension . what was your mash schedule and OG and starter size. this yeast should have done fine in the mid to high 50’s-similar to kolsch 029.

3

I started the partial mash at 152F for an hour although temp was at 144F at the end. OG was 1.052. Yeast starter was the White Labs instructions of 2 pints water and 1/2 cup DME.

4

so that’s a small starter. you had about 940ml starter at 1.042OG producing about 230BB cells. and even with fairly fresh yeast that’s not enough -especially for cooler fermentation. i would target 275BB-300BB , so around 1800-2000ml at 1.030OG.

also the mash lost a lot of heat over an hour. using a cooler? may want to upgrade to thicker wall cooler if your losing that much heat.

edit: what was date on your yeast? generally, 1000ml is smallest recommended amount of wort for starter. smallest i use is 1400ml and i target lower OG of 1.030-1.032. using a stir plate or shaking? i use http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/ to determine my starters as well as prior experience with the recipe and yeast.  like i mentioned, i shoot for more yeast cells for cooler fermented ales.

5

Did you record the SG of your starter?  With that ratio of malt to water, without my notes in front of me, it looks like it may have been a bit high…  Depending on where you look you’ll see a goal roughly between 1.03-1.04.