I’ve brewed a Russian Imperial Stout in Jan. 06th, with an o.g. of 1.084 and a target f.g. of 1.020, but it’s been 1 and a half week that it got stuck at 1.033.
I’ve used 2x. S-33 yeast for a 18L batch (4,75 gal.) and it fermented between 64°F and 68°F for the first 14 days, and between 68°F and 72°F to this date.
How can I convince my yeast to keep on attenuating?
thanks
Move the fermenter to the warmest room in the house and give it a couple weeks, then check gravity. The moving of the beer will gently rouse some of the yeast into suspension and the warmer temp might spur the yeast to eat a little more sugar. Big beers often take longer to reach FG. You should post your recipe and process so we can see any potential issues. And welcome !
That’s plenty of yeast for a 1.084 beer. Have you calibrated your hydrometer in water to be sure it reads accurately ? And what thermometer do you use for mash temps? A cheap thermometer could’ve had you mashing several degrees warmer than you assumed. What mash temp?
Edit - And did you aerate thoroughly before pitching? Bigger beers need to be aerated even more thoroughly than average strength beers.
Im not a very experienced brewer. This is only my 9th batch and I was concerned about the yeasts ability in fermenting such high gravity wort, but obviously, I was wrong.
Actually, I used a regular hydrometer (not the fancy refractometer type) and it requires no calibration, I guess…
I used a digital, 0.1°C/F accurate thermometer. Mash temp. was between 142 and 152
Regarding aeration, I used a small duly sanitized aquarium air pump hose and stone with a 0.2micra air filter. I placed the stone in the fermentor before slowly transferring the wort to it, so that it was being aerated all the time (about 30 min.).
So, did I do something wrong here?
Hey ,we all started somewhere. Hydrometers can be checked for calibration - before brewing each time place it in a glass of water and see if it reads 1.000, correcting for temperature . If not , you’ll need to add or subtract the deviation from your readings. But the mash temp seems to be an issue - describe what you mean by the 142 -152 mash temp. That’s a huge temp range. Do you mash in a cooler or a pot? Did you stir the mash thoroughly enough to get a consistent reading ? How long did you mash?
Thanks for the calibration tip; I’ll do it from now on. Sorry about the temp. range. What I meant was 148°F to 152°F. I mashed it in a large aluminium pot with a false bottom, stirring almost all the time for 70 min., and I kept doing vorlauf for the last 20 min… Iodine test confirmed full saccharification.