Just bought a 14cuft fridgedaire freezer,and installed Johnson controls a419. Curious about people’s experience with accuracy of temperature for the unit, and if you find better accuracy with thermowell or just taping probe to side of carboy with bubble wrap or foam covered with tape.
I’ve set it to 52F, with ±1F on/off.
I tape it under some foam and it’s always right on for me. I have a 7 cuft chest freezer. If I have two fermenters in there I just trap the probe between the two.
I don’t even bother with the foam. Whatever your fermenter is made out of, it’s a couple orders of magnitude better conductor than air.
Do you use 1 or 2f± differential? I’m thinking if my ideal temp is 52f, is set it to shut off at 51 and on at 53…or 1f differential.
I use 1 degree as the differential.
Got it. I read most set the ASD to max of 12 minutes- any thoughts on that?
I keep mine at 10 minutes.
Strap it to the side of the fermenter in some way and a little covering to insulate doesn’t hurt. Even an old washcloth works for that so no need to get fancy. The point is to always measure what you want to control and that is the liquid temp of the beer, not the air temp of the fridge.
I don’t understand the reasoning behind insulating the probe. Couldn’t that potentially cause you to overcool the beer in the fermenter?
If the probe is well insulated, and you’re looking to cool your fementer down 10+ degrees- it’s going to take a while. In the meantime, your chest freezer keeps plugging away. By the time your beer gets down to the intended temperature, the air/wall temp is well below your set temp. Wouldn’t that cause your fermenter to keep getting cooler before eventually equaling out?
Yes, it will drop a bit more, but the thermal mass of all that liquid is so much greater than the air and walls of the fridge/freezer, so the effect is minimal. IME, that additional drop is usually less than one degree F.
that and it stabilizes pretty darned quick.
I create a pouch with velcro to affix my probe to the side of my fermenters.
Tape doesn’t work for me, it always falls off. I put the probe under some bubble wrap between the brew hauler and the carboy. I think it stays pretty accurate, certainly with in a degree or two.
Bungie cord and a scrap of foam. For 10+ degrees drops my fridge will sometimes overshoot by a couple of degrees. I set the temp accordingly, then tweak if necessary. Since this isn’t during fermentation I’m not too fussy about it.
I agree with the insulation of the probe. The one surface area of the probe is snug against your fermentation vessel, and the exposed area of the probe is insulated with foam, bubble wrap, or cloth- keeping it from ambient air shifts that would happen when freezer kicks on or you open the lid.
I place mine in a thermowell inserted into the fermentor so that the probe measures the very center of the wort being fermented… I worry about my wort’s fermenting temp, not the temp of the probe hiding under the insulated material. Many agree that the yeast will create a temperature increase within the fermenting vessel which can be anywhere from 4-8 degrees higher than the ambient temperature surrounding it…just because we cool off the fermentor and the ambient air surrounding it, doesn’t mean we no longer have any type of temperature increase from the active yeast, does it?
All I can say is that it sure is easier brewing a lager with a set it and forget temp controlled lager freezer ;D
Ice baths and constant monitoring was a buzz kill…literally :o
+1. Next you will want a second chamber to store in for bulk aging…
Posted by: ynotbrusum
« on: Today at 05:34:57 AM » Insert Quote
+1. Next you will want a second chamber to store in for bulk aging…
Shhhhh…my wife can hear you! 8)
While it’s true that ambient can be much warmer than actual wort temp, when you place your probe in contact with fermenter and insulate it, you’re not measuring ambient - you’re within no more than +/- 1 degree of the wort temp.
I used to think the same as your quote above, but I am one who questioned it the more I thought about it…So I performed an experiment placing three thermometers inside my fermentation chamber. T1 was placed in a thermowell at the center of the glass carboy. T2 was taped to the outside of the glass carboy half way up its height and then insulated from the surrounding ambient air in the fermentation chamber. T3 was placed inside the chamber only to read ambient temps. Throughout the fermentation process all probes were within a degree of each other until the yeast activity began to really ramp up. At that time, T1 would follow the increase in yeast activity. T2 would lag behind a couple degrees and T3 would continue to read the ambient which was nearing 1.5 degrees lower than T2 which was 1.5-2 degrees lower than T1 which was reading the interior of the vessel. So at max yeast activity, there was a 3-3.5 degree spread between ambient and internal temps. Now if I want my yeast to ferment a lager at 52F, I want my yeast to ferment at 52F…not 55-55.5F…Ergo, the temp controller is hooked to the probe reading the internal vessel temp, not the other two… YMMV…If you have not performed this test on your own fermentations you may want to give it a try… cheers!!!