Originally Posted by Peregris
I've got a batch of Helles lager going, and after 8 days or so fermenting at 50 degrees the bubbles slowed down considerably. I took it out of the fridge for the diacetyl rest and the bubbles sped up quite a bit - so much that it looks like at the height of fermentation again. Is this normal or did I take it out too early? Will I get any estery flavors or should it be safe?
I didn't want to open it up to check the spef. gravity for fear of contamination or oxygen exposure. In the future - is it okay to open it up at this point to check the hydrometer reading?
Note: I used Saflager S-23 Genuine Lager Yeast.
First off, I take hydro readings all the time and it's never led to a contamination. Just practice strict sanitation and you'll be fine. Soak your thief/baster/etc. in star san, et al, prior to taking the sample---also make sure to sanitize your hands somehow---I either soak my hands in star san for a minute or I just use purell hand sanitizer. Not that your hands will or should ever touch the beer, I just find this to be an extra precaution. If you have any air circulation in the place where you'll be taking a sample, turn it off. Don't do anything just prior to taking the sample that will rouse an extraordinary amount of dust from any surfaces.
Now, I say all of this, but in reality, the most important thing to do is sanitize the thief...risk of bacteria, etc., falling into the beer is very small because of the positive co2 pressure from fermentation. Pop the bung/cap off the carboy, grab a sample, dump it into the hydro vessel, put the cap/bung back on. The chances of anything infecting your beer in that short a time are minuscule. Hell, I've had bungs pop out overnight and stay that way, and the beer is still fine.
So, never be afraid to take hydrometer readings! And be sure to never add the sample back.
Now, as for your d-rest question---if it was starting to slow down, then it was on its way out, and you did the right thing by taking it out for a d-rest (especially with the saflager!). Yes, the yeast may get working harder again with the higher temps, but chances are, after 8 days of fermenting, they're past the point where higher temps will result in ester production. So just RDWHAHB and let it finish fermenting in the 60's until the krausen drops, then bring the temps back down. If you bring the temps down before it's done, it might shock the yeast and end up with unfinished wort.
You did the right thing.