Stuck Fermentation

Hi guys,

I brewed a Blonde Ale (all grain) recently and I’m having issues with my fermentation. My OG was 1.040 and I was targeting my FG to be 1.008. Four days after active fermentation started, it stopped at 1.021. A week later and it’s still 1.021. I used a 2L starter with 3 packs of White Lab 001 (California ale yeast) on a stir plate. Pitched at 68* and was fermenting at 70*. Am I missing a step here? Does anyone know what I’m doing wrong?

Gotta be the recipe or process.  I’d just wait a while and see what happens, though.

How are you measuring gravity?

Either your mash thermometer is messed up, or your gravity measurements, or your recipe.  Calibrate your tools, if using a refractometer then correct for alcohol content, and… post your recipe so we can see if that contributed, including mash temperatures and times.

Here is my 5-gallon recipe:

9 lb 2-Row
.5 lb Crystal 15
1oz Willamette
Whirlfloc (1 tablet)
Servomyces Yeast Nutrient (1 pill)

Strike water 162*
Mash 60 min at 153*
Boiled for 60 min

I use both a refractometer and hydrometer. I’m also using the Plaato airlock and all are the same readings.

Recipe looks good.  Problem is either instrument error / failure to calibrate, or other operator error.

That’s a lot of yeast.  With that recipe I would think you could get away with 1 pack and no starter.  At this point thinking all you can do is ramp up the temp a bit to see if encourages more fermentation or add more yeast…

If nothing else works you can always try a dry wine/champagne yeast like Lalvin EC1118, but that might take you down well below your 1.008 target.

It wouldn’t cause a stuck fermentation, but that seems like a pretty inefficient use of yeast.  Considering maximum cell density is around 200 billion cells per liter, the most you would have ended up with is 400 billion cells (which isn’t much growth considering you started with around 300 billion; unless the packs were really old or otherwise of low viability).

Assuming you will grow around 100 billion cells per liter of starter wort, you could have gotten a similar cell count by pitching one pack into a 3 liter starter.