This may be a silly question to experienced lager brewers, but I have some concern about the Oktoberfest I am fermenting.
This is the first lager I brewed. I wanted to control the fermentation temperature at 51 degrees. That is where the external temperature controller is set. Every time I check the freezer temperature, (on the digital read out on the controller) it is reading in the mid to high 40’s. I figured that the balance of the temperature swing should be about 48 degrees. Today I bumped up the set point on the controller to 54 degrees hoping to bring the beer temperature up 3 degrees. What effect will the cooler fermenting temperature have on the beer?
Another thing I am concerned about is the fermenting activity. There appears to be very little. I have been fermenting this beer for 5 days. I have a blow off tube in place thinking that there will be a good chance that Krausen will be spewing out all over the place since I made a two step starter. This happens with the Ales I make. So far there is minimal Co2 activity. The Krausen layer has not increased since the third day. Is this the nature of a lager? Or is it because of the lower fermenting temperature? Or worse can there be an infection?
Thank you
Brad
Is the temp prob reading air or beer temp?
Lagers normally have a small krausen. My experience has been about a 1" krausen.
The probe is lying next to the side of the of the carboy, so it looking at the air temperature. I wanted to use the suggestion of wraping an ace bandage around the probe and carboy, one of those things that had good intentions but never got done.
There is about an inch or so of Krausen on top of the beer. If it has an infection I know where it came from. I needed to top off with about a 1/2 gallon to get the OG in range and I used water from the carbon filter. The filter is flushed out good, but bacteria may be lurking. I only use it to fill the mash and sparge kettles.
Stop fretting about an infection. 
It is not.
If measuring air temp, you should not see the temp reading go but 1-2 degrees below the “swing” setting. Example: Setting 51* and a 2* swing. So the fridge will shut off at 49*. But, there will be some stored cooling in the walls of the fridge. So the temp may drop another 1-2 degrees.
Same thing could happen if you had the temp in/on the beer. But I think it’s less likely the beer would drop in temp.
Sounds like thing are “normal”.
Man Nighthawk I hope your right about an infection. If I would have used water from the tap instead of the filter I would feel better.
I watched the temperature on the controller the other day. When the controller came on at 51 degrees the freezer temperature started to drop. At 50 degreese, the controller relay opened and stoped the freezer but the temperature continued to drop to 45 degrees. The temperature slowley recoverd, it took a while. The temperature drops a lot faster than it does warming back up which makes me think the beer temperature in the fermenter is 3-4 degrees colder than what I intended because of the slow recovery.
If your probe is reading air temps, this is the way refrigeration works. You set the temp you want and it kicks on several degrees above and off several degrees Below. If you are watching the temp fall after the compressor cuts off, it is just because of the lag of getting to your probe.
I put my probe in a plastic bag and place in a quart water container to not show the air temp swings.
[quote=“Bier brauer”]Man Nighthawk I hope your right about an infection. If I would have used water from the tap instead of the filter I would feel better.
[/quote]
A friend uses a carbon filter. He was told by his water guy that if he kept theme filled and under pressures nothing would grow in them. So he has a shut off before and after the filter. Shut the “after” valve off. Then the “before” valve. Then then the water is trapped and under pressure.
Or you need to dry them out after using.
Still, stop fretting.
The probe in the water is a great idea! Talk about not thinking, that’s how I have the thermometer set in the beer machine! Wow! Why didn’t I think of that :oops: Gonna set that up before I go to work today.
When I first bought the carbon filter, after the first use I took it apart and let the filter sit and air dry. The guy at the water treating facility told me I have to buy a new filter every time I brew because it will not dry out and bacteria can grow in it. Since we boil the wort, that should take care of the little critters. But I used it to top off the water in the carboy. That’s not gonna happen again!
I did a variation of the probe in the water set up. I had the probe in the water for two days. It seemed to react slow. So I took the probe out of the water and placed it half way down the side of the carboy,then placed one of my brewing thermometer in the water. Now with the temperature swing in the freezer, I can see the what the liquid is temperature is doing. So far seems to be sitting at 50 degrees.
You actually WANT it to be slow to react! That is the point of putting it in water…so that you more closely resemble the beer liquid, which is also slow to react to temp swings.
When your probe is out in the air, it reacts every time the compressor kicks off and on. Turns it on too fast and often and also turns it off too fast.
You need to figure this system out and quit worrying about it. I pitch my yeast and check a few days later to make sure it is fermenting, which I know it is, because I use starters. I will check the temps about once every other day just to make sure the refrigerator is still working.
I make my lagers in the garage during the winter. I get temps swinging between 38F and 50F. It slows or speeds up the fermentation, but so far, hasn’t affected much in my opinion. I made 35 gallons of pilsner lager last winter ( and another 10 gallons of a dark brown lager). Active, healthy yeastie buddies seem to do their job, they just slow down a little with reduced temps.
