Strike Temp Calculations

Hey everyone. I use iBrewmaster to calculate my strike temperatures. I've noticed, though, that for some recipes, the strike temp is perfect and I hit all my numbers with ease. Other times, however, the strike temp proves to be woefully off base. I can't conceive why this might be since it's the same program each time with the same equipment profile that accounts for temperature loss in my system. Anyone else have this issue? If so, how have you overcome it?

Yesterday was one of those times that it was really off. I was making the Union Jack IPA, which has a Sacc rest at 145. I had 20 lbs of grain and I use a cooler. Program told me to strike at 161. Seemed reasonable. Not so much. I blew by my target mash in.

Are the temperature of your grains the same? The amount of hear the absorb could be throwing it off. Sounds like that's the only variable you didn't mention.

Was the cooler preheated?

tyzippers said:

Are the temperature of your grains the same? The amount of hear the absorb could be throwing it off. Sounds like that's the only variable you didn't mention.

Click to expand...

Yes, that's the only variable, I agree. I didn't take the Brian's temp, but they were both stored in the same place, and while there might have been some variation, I missed my mark yesterday by about 7 degrees. Hard to believe that grain temp can vary that much, no?

phuff7129 said:

Was the cooler preheated?

Click to expand...

Nope, but it never is. I have the program assume a two degree loss, which is a number based on my testing of the water temp before I toss in the cooler compared to afterwards.

Assuming your thermometer is accurate, there are really only two variables: the temp of your cooler and temp of the grains, cet par. So eliminate one of those by putting the water in the cooler for several minutes until it stabilizes. Track the temp of the water in the cooler just before you add the grains, and adjust it if needed. And always use the same water to grain ratio. So the only variable left is grain temp. You've just cut your variance dramatically.

If this sounds confusing, keep thinking it through and you'll see the simple brilliance of it.

Here's what I do. I use a cooler too. My grain temperature is almost always between 65-70. Let's say my mash temperature is going to be 152 as an example. Easy. I just pour in water that is 20 degrees higher than my mash temperature. In this case it would be 172. This gives you some play room. The initial temperature will drop just a little when it hits the cooler. Add your grains and stir and at some point so you should settle on your mash temperature. If anything the temperature may settle a little high by a few degrees. Stir some more or add some cold water and stir. I usually stir. IF it ends up a little cool simply add some hot water and stir. I have been doing this for about the last 10 batches and am pretty damn close each time. Never been too cool yet. Usually I am high by somewhere between 2-5 degrees. I just stir for a minute or so and am good to go once it hits 152. Never made a bad batch yet. Just my stupid humble opinion though Have fun and drink homebrew.

I lose 2-3 degrees when pouring from the pot to the cooler. Then I lose 10 degrees when I stir in the grain. It took me two batches to lock in these values for my system. I've made everything from a 1.045 session to a 1.085 Tripel and these values are within a degree of what I've stated here. I never miss by more than one degree using my default 13 degree value.

All you need to do is find, record and use these values. It's so easy to do you don't need a calculator.