Mash Temperature Techniques

[Golddiggie]

I've had pretty much all the BB&B purchased digital thermometers (instant read) fail on me after using them for brewing. They don't seem to have the electronics sealed, or sealed well enough, to survive. The Fisher models are solid, and call out either waterproof, or damned close to it.

I used a candy thermometer early on in my brewing life. It failed after about 2-3 batches (had it clipped to the side of the pot, so that I could see the temperature). It was digital and too much moisture got into it and killed it. I also don't use the oven probe thermometer for brewing. I did that one time, to see how it would work out and it wasn't even close on the reading. It was ok in the lower temperature range, but once it started getting past about 150F (maybe 160F+) it was drifting a lot. Not something I would trust for a mash tun. I'm sure there are good units out there, it's just not what I have. It's fine for a roast, and such (usually under 140F anyway) just not something I'll use for brewing.

 

[Wynne-R]

This a great topic. There is a lot of discussion about temps, but not much about methods and measurement.

Personally I rely on strike temperature, stir well and put it in the oven.

The best method I have found to measure the mash temp is to attach the sensor to the mash paddle, though it’s awkward. I wish somebody would market a paddle/thermometer combo.

It’s a little off topic, but would somebody tell me how much variation there is in an active fermentation? I say the top center of the fermenting wort is 5-10°F hotter than the outside of the carboy. The conventional wisdom is that they’re about the same and I think that’s absurd.

 

[Yooper]

This a great topic. There is a lot of discussion about temps, but not much about methods and measurement.

Personally I rely on strike temperature, stir well and put it in the oven.

The best method I have found to measure the mash temp is to attach the sensor to the mash paddle, though it’s awkward. I wish somebody would market a paddle/thermometer combo.

It’s a little off topic, but would somebody tell me how much variation there is in an active fermentation? I say the top center of the fermenting wort is 5-10°F hotter than the outside of the carboy. The conventional wisdom is that they’re about the same and I think that’s absurd.

In my experience, during an active fermentation the beer is churning pretty well, and the temperature of the beer varies very little throughout- about a degree at the most.

 

[Golddiggie]

In my experience, during an active fermentation the beer is churning pretty well, and the temperature of the beer varies very little throughout- about a degree at the most.

+1 on that. I have a thermowell on my sanke fermenter cap that goes into the middle of the fermenting beer. I trust that temperature reading far more than on the outside. I want to know what the majority of the batch is fermenting at, not the last 1/2" from the outside.

 

[MalFet]

+1 on that. I have a thermowell on my sanke fermenter cap that goes into the middle of the fermenting beer. I trust that temperature reading far more than on the outside. I want to know what the majority of the batch is fermenting at, not the last 1/2" from the outside.

I used to do that, until I actually ran a bunch of comparison tests to see the difference between the thermowell's temperature and the temperature of a probe taped and insulated to the side of the (ss) fermentor. Even during the most vigorous fermentation, I never saw more than 1/2 ºC difference. YMMV.

 

[Wynne-R]

1°F, really? I saw 5° on a floating thermometer compared to the stick-on lcd thermometer. That was before the krausen engulfed the floating thermometer. Does it make a difference that the carboy is in a water bath?

 

[MalFet]

1°F, really? I saw 5° on a floating thermometer compared to the stick-on lcd thermometer. That was before the krausen engulfed the floating thermometer. Does it make a difference that the carboy is in a water bath?

Insulating the probe tip is key, otherwise you'll just read some kind of average of the wort and the ambient air. I'm not a huge fan of the LCD stickers for this reason.

 

[Golddiggie]

I also plug up the top of the thermowell, so ambient air doesn't impact the reading.

Plus, with the thermowell, there's less things to move to another fermenter.

Not saying either is better than the other, just I like what I do better than trying to take readings from the outside.

 

[sengsational]

You all are way smarter than I am! But I doubt anyone has spent less on their equipment, hehe.

Consistency of the el-cheapos I got from Hong-Kong - So far very accurate. I've had them for about 3 months, tested them all at boiling and ice when I first got them, but didn't have the allafrance lab thermometer to calibrate. I tested them all again recently and they came in the same (within .1 degree C). Like I said three of them were spot on together, and two were in left field, but they too were consistenly off. If they ever get inconsistent, I'll order another half-dozen from Hong-Kong.

About mash temperature varying with position - Obviously depends on the equipment, but I brewed last weekend with the three probes. I placed the probes (roughly) bottom outside, center inside, and top outside (in a diagonal). This was a cylindrical insulated mash tun (rubbermaid, I think it is, $42.88 delivered). I stirred well, but obviously the outside is going to be loosing heat faster than the center, and that's what I saw. If I stirred again, the differences became less, but when folks are making a big deal about exact mash temperatures (150F vs 152F), it's a bit disconcerting to see temperatures larger than that that are, and I maintain it's true, just inches from each other. But I also agree with the comment that it's probably good to have a mix of temperatures.

The rest of it - Like I said, you're all a hell of a lot smarter than I am, hehe.

--Dale--

 

[MalFet]

Consistency of the el-cheapos I got from Hong-Kong - So far very accurate. I've had them for about 3 months, tested them all at boiling and ice when I first got them, but didn't have the allafrance lab thermometer to calibrate. I tested them all again recently and they came in the same (within .1 degree C). Like I said three of them were spot on together, and two were in left field, but they too were consistenly off. If they ever get inconsistent, I'll order another half-dozen from Hong-Kong.

Great!

I certainly didn't mean to come down on every cheap thermometer. There are plenty of good ones out there, even for small money. I would, however, recommend testing again a few months down the road...once the batteries have faded a bit. This, I suspect, was the principle source of tbe problems that I saw.