Odd Air lock behavior in Ferm Chamber (min-fridge)

**terrapinj** · 09-29-2011, 01:23 AM

Finally bought and modified a mini fridge to use as a ferm chamber with the a-419.

I have the probe taped between a gel ice pack and the bucket and the reading is usually +/- 1° of the wort temp when checked with a thermometer.

I noticed a few times that the blow off would quit bubbling shortly after or during the fridge cycling on. I thought at 1st that perhaps the wort was getting too cold and stalled the yeast out or less likely that it finished in less than 48 hours ( wyeast 2112 in 1.057 @ 60°)

this morning I changed over the blow off tube for a reg 3 piece and it was bubbling away steadily. When I came home today the fridge had recently finished cycling and the airlock was completely still. even slightly depressing on the lid doesn't release co2 like it normally does.

I'm not at all concerned about whether or not fermentation is done (there is still krausen and still been less than 72 hrs) and I think Revvy once mentioned somewhere that a hydrometer is a helpful tool

I plan on leaving it in there and slowing ramping temp up to about 68° by the 3nd week or so to make sure it finishes, diacetyl rest etc and then rack to a keg to psuedo lager for a few weeks.

i'm curious if anyone has seen anything like this due to temp differences or pressure differences etc. due to the fridge cycling.

**jeepinjeepin** · 09-29-2011, 01:29 AM

It makes sense that it would do that. Are you familiar with the Ideal Gas Law? You have Temperature, Pressure, and Volume and changing anyone changes one or both of the others.

Just ignore the airlock and after a week or 4 measure the gravity.

**terrapinj** · 09-29-2011, 02:13 AM

pv=nrt?

been a while since I took chem but i assumed it had something to do with that

I never really use the airlock for a gauge for anything, just found it odd it would keep starting and stopping

**terrapinj** · 09-29-2011, 02:37 PM

Thought about this some more. With a 1deg difference there really shouldn't be too much different pressure inside and outside

Anyone else experience this?

**terrapinj** · 10-04-2011, 04:51 PM

so this had nothing to do with gas laws, pressure differences etc.

for some reason the lid which has been used for several batches isn't sealing in one spot

checked gravity last Friday on day 6 and it was at 1.016 and krausen had dropped already