Where in MLT to Measure Temperature?

So if I stick my thermometer all the way down to the grain bed, it measures 154. All the way on top, just below the surface of the water, it measures 150. Which is the temperature that I should consider when trying to hit my numbers?

Thanks.

Well....don't take this the wrong way, but how accurate is your thermometer? I should think that the temperature in the grain bed would be the important one, but I've read threads on this and other forums that make me suspect that questions about a four degree Fahrenheit difference should lead first to a discussion of thermometers, and only then to a discussion of the temperature gradient in the mash tun or MLT.
I would seriously like to see more discussion of this, as I'm just beginning the transition to AG myself.....

I use one of those long, skinny, lab thermometers. Was sick and tired of erroneous thermometers...

The grain bed is where all the action takes place, so I would try to keep it there. I do stir my mash a couple of times during the hour to try to keep temps equalized a bit.

I had the same problems
I'd take a temp and it would be way low so I'd
rush around trying to heat up water to raise the temp
then check it again and it's right on (or at least close enough )
Now I take the thermo and stir it around to try and get an average

mgo737 said:

I use one of those long, skinny, lab thermometers. Was sick and tired of erroneous thermometers...

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I used a lab thermo for the same reason. I since found out that it was 3 degrees off every other thermo that I own.

Anyway, I found that with te lab thermo I needed to swish it around a lot to get an accurate reading. It seems to take a while for the glass to get up to the surrounding temp, and it even cools the wort down that is immediately around it when you first put it in. Overall, I don't rate the lab thermos as highly as I thought I would. I have two meat thermos from walmart that have proven to be more accurate at mash temps!

mgo737 said:

So if I stick my thermometer all the way down to the grain bed, it measures 154. All the way on top, just below the surface of the water, it measures 150. Which is the temperature that I should consider when trying to hit my numbers?

Thanks.

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It may help to know where the "sensor" of your thermometer is. For example, if it's 3/4" away from the point, and you only stick it in the first 1/2" of your mash, it may give a false reading.

Also keep in mind that different readings in different portions of the mash may mean dough-balls (i.e. mash not mixed well enough), even if visually it looks like it's mixed

Have you tried looking for accuracy of your thermometer? Coz mine was not accurate as it boasted. Now i m currently using, skinny, lab thermometers. Those are really good to work with.