Insane krausen with expired yeast

[kukubau]

I've just made 6 gallon (hard) cider using nonpasteurized apple juice. As I had a bag of Safale S-04 yeast that was long expired for about 2 years, I've thought of building a starter with some DME using my new bought stir plate. After 8 hours it's bubbling like crazy and I've never seen such a strong krausen. The yeast bag wasn't properly stored, it has seen up to 40°C. Could it be that using a starter using the stir plate, have grown such a healthy number of beasties? I've added a small amount of of yeast nutrient, but I doubt that had made such a big difference. It's amazing how strong the airlock activity is and the krausen level in the fermenter. I had to clean the airlock 5 times already.

 

[MarkKF]

Picture please. It sounds amazing. How much headspace do you have? Any added fruit?

 

[kukubau]

No added fruit. Headspace I would say 10 cm from Demijohn's neck base down. Pictures coming next.

 

[kukubau]

Krausen

View attachment 1481871566170.jpg

 

[ten80]

That's pretty typical for S-04, I had a similar krausen with a cider I just did this fall. You have to keep the temperature down around 56-58F to keep the krausen under control, then ramp slowly to 65-70F for complete attenuation and "cleaning up"of the beer.

S-04 is a resilient yeast. I'd not hesitate to use old packs as long as they haven't seen over 30 C (85 F or so). 40C is really cooking though!

 

[MarkKF]

I've used S-04 for a few years and never had more than an inch. Usually in the mid to low 60's deg. F.

 

[kukubau]

Probably it's due to my stir plate. I've let it spin for 36 hours with some DME, then I've decanted the DME and washed the yeast with clean water, before adding it to the carboy.

 

[kukubau]

As said, I've been blown away as well as my Demijohn's bung I never thought a stir plate & starter could make such a huge difference with expired yeast. I'm curious to see how it turns out with S04. Next I'll start fermenting 13 gallons with WLP775 and age that until summer.

 

[MarkKF]

I'm a big fan of S-04. Stops at 1.004 everytime when I start at 1.054. No off flavors or odors.

 

[ten80]

Agreed, its a great yeast and flocculates nicely. Starters will really get it cranking, so i try to pitch it slightly below 60f to keep the krausen manageable. The only downside to fermenting so cold is that the fermentation may be TOO CLEAN! Sometimes a little yeast character (from esters, etc) does add to a beer, so this is something to consider.