Oh no!

Mashing
1

Long story short - I found out as I was getting ready to pitch yeast, that the digital thermometer I was using during the ENTIRE PROCESS may have been BAD!!!

Quick details: Denny’s Wry Smile IPA grain bill was too large for a single go with my small BIAB set-up, so I split everything 50/50 and mashed with two kettles. I have two identical digital thermometers I have used for the past couple of years for everything, and they have always been fine. …that I know of.

Through the mash process and then during cool-down, the temps in both thermometers were reading the desired temps, so after cooling, I dumped everything into my primary and got ready to pitch the yeast.

For some reason, the little voice in my head said “check it again” before I pitched, so I took ONE thermometer and checked the temp. 90 degrees.

What the…!!! It was just 66!!!

Oh well, maybe one of the probes was too close to the chiller, so, make sure the chiller is still sanitized, and chill it some more.

Well… I start the chiller, and realize this particular bucket doesn’t have a fermometer on it, so - I have a new one - I put one on it.

Now the temp on the fermometer reads 58!

WHAT THE…??? I yank the chiller, and grab the OTHER digital. …58!!!

SON-OF-A…!!!

So… after checking, one digital is now giving me inconsistent readings. I have no idea how long I’ve been getting inconsistent readings.

I DID hit my O.G. just fine, so… What would be the effect of doing half my mash at a temp roughly 25 degrees cooler than the “ideal” 153??? Did my thermometer crap out after mashing (because I hit my O.G. therefore my mash was successful?), or who knows???

Thanks for any input!

2

Is one thermometer giving inconsistent results, or are they consistently off by a certain amount? It is not clear to me from your description that the mash temp was 25F low. If the mash was 25F low, the alpha amylase would have had almost no activity, and all the conversion would have been accomplished with beta amylase, making pretty much all the converted sugars fermentable. But if it was only a 60 minute mash, it is unlikely that total conversion would have occurred, meaning that unconverted starch in suspension accounts for some of what you measured in your gravity sample.

This is one of the problems with digital thermometers, they can go bad in many different and sometimes strange ways (it could have been accurate at 153, and off by 25F at 90 for example), and unless you check them at the temperature you are interested in, you won’t know it is bad.

3

Just one thermometer seems bad. …and I might be seeing your point to it being off “different amounts at different temps.” …it’s just inconsistent.

I do NOT know if my mash temp was off or not; the thermometer may have been bad all the way through, or it could have crapped out right at the end. I don’t know. It was a 60 minute mash, so I guess I’ll find out in one to two weeks! LOL!

…and I guess I’ll be looking at buying a couple of different thermometers as well!

4

I use a bimetal thermometer with a long probe on it and use a lab thermometer to frequently calibrate at 150F.

5

Please take it from me: thermometers are one of those things on which you can spend hundreds of dollars over years of brewing and wind up with a drawer full of junk, or spend the money the first time, and get something that you know is accurate. These are also indispensable if you like to cook meat. At all.

I am all about Thermoworks’ products (most popular is the Thermapen), but some say they are for meat, not liquids. I have calibrated mine with the ice bath and boiling liquid tests (but not a lab thermometer…which I have also heard horror stories).

6

I also use the thermapen, and really like it. But I don’t trust it blindly to keep accurate. Bimetal thermometer are very good overall, and while they might jump out of calibration suddenly if knocked hard enough, they rarely drift. The dial thermometers that you can screw into your brew pot are typically made with bimetal elements. As I use my kettle to heat mash water, simply dipping my thermapen in at the temperature I am interested allows for a comparison between the two. As long as they are in agreement, I figure it is very unlikely that they have both shifted out of calibration by the same amount at the same time.

Lab thermometers are more accurate and stable than anything else you can buy, but they are both expensive (if the calibration is guaranteed) and fragile. If you try to use one of these to measure your mash as part of your normal process you will likely eventually end up with broken glass and measurement fluid (typically alcohol dyed red or mercury) contaminating your mash. So they are best used as a standard that is used to confirm accuracy of your working thermometers.

Frequent calibrations like Denny gets would be great, but they can be expensive. It would cost me several hundred Euros to get a thermometer calibrated to NIST standards locally.

7

I bought a Fluke digital thermocouple thermometer.

http://www.amazon.com/Fluke-Digital-Thermometer-Battery-Rejection/dp/B003ZB36PW/ref=sr_1_29?ie=UTF8&qid=1425416842&sr=8-29&keywords=fluke+thermocouple+thermometer

$300, but worth every penny…

8

Wow, lots of money for a good thermometer!

I have a couple that I tend to use. To ensure they are accurate still, I do the ice water/boiling water testing as well. I always use two in the hopes that both of them certainly can’t be wrong :lol:

9

[quote=“Templar”]Wow, lots of money for a good thermometer!

I have a couple that I tend to use. To ensure they are accurate still, I do the ice water/boiling water testing as well. I always use two in the hopes that both of them certainly can’t be wrong :lol: [/quote]

That’s great as long as you mash at 32F or 212F! :slight_smile:

10

[quote=“Denny”][quote=“Templar”]Wow, lots of money for a good thermometer!

I have a couple that I tend to use. To ensure they are accurate still, I do the ice water/boiling water testing as well. I always use two in the hopes that both of them certainly can’t be wrong :lol: [/quote]

That’s great as long as you mash at 32F or 212F! :slight_smile: [/quote]

:lol:

Still learning the ropes with every brew! But they both read pretty closely during my last brew at all steps in my mash. Eventually I’ll get around to getting them calibrated/fixed if they seem to be off. When the wife stops yelling at me for spending so much money that is. :cheers:

11

I wasted a lot of money on digital thermometers and screwed up a couple of batches. The guy at the homebrew shop recommended old fashioned long stem dial thermometers. That’s what I use and never a problem any more.

12

Yeah… looks like I’ll be moving away from digital…

13

What I did grab on sale is one of those laser thermometers that are kind of neat. I shoot the fermenter it tells me the temp. I shoot the kegs that are lagering. I also shoot the walls and floors to find cold spots. I tried it on my wife also. My cat likes to chase the beam. All in all for $12 of entertainment it was worth it. Wouldn’t trust it on my mash temp though. Trusty old dial style for me.

14

So, is your wife hot?

15

So, is your wife hot?[/quote]

Uh oh… :lol:

16

I think you guy are on the wrong forum, but yes. Answer to your next question is no.

17

:lol:

18

And now you have emperical proof of it. But come on, not even one taken with a thermal camera? :roll: