Brewhouse Mash In Temp Problems

[Alphaacid]

I have a 3 vessel, 5bbl brewhouse system, and I am constantly missing my mash in temp by up to 3F. It's driving me fucken crazy. Here is my process:

Heat up boil kettle to a boil, running through my heat ex, until it reaches a boil. Then I put the boiling water into my mash tun, allowing the MT to heat up so when I mash in my temps don't drop 5F immediately. I let the hot water sit in MT, then drain MT. I take a temp of my grains, and make sure my HLT is at proper temp. Once MT is drained I begin to add water from HLT adding my grains after about 1-1.5bbls or when the temp reads about 3-4F above my mash in temp. I add the grains trying to maintain temp. About 50% of the time I hit the target right on, but other days I don't. It's frustrating.

I know some will say don't heat up the MT, I've tried this but the insulation sucks all the heat out of my mash dropping temp 5F within 10mins, 10F within 30mins, and at the end of the mash I'm around 15F below my mash in temps.

I really can't figure out how to get a more consistent mash in temp. Maybe I need a water blender?


HELP!!!!!

[jebzter]

Your HLT water may have some temperature stratification in it, that could be an issue. Are you continuously monitoring your strike water temps or just letting it go once you hit your temp? As a rule of thumb, I run my HLT hotter than needed for strike water and blend it with cold water to get to my strike temps. I make adjustments as required to keep it consistent, but also check the mash temp throughout the process to make sure I keep it on target. Never off by more than a degree. Your temperature offset seems a bit low to me, so its either really hot where you are, or your mash is very thin, but I typically see a 15 ish degree drop in strike temp when we mix with grain, ambient temps are 65 or so.

[Alphaacid]

Ambient temp is 65-72F depending on time of year. My mash is 1.3-1.5 qt/lbs. I get into the HLT with a paddle and give it a good stir to make sure it's uniform. I don't have a blending tap, I take straight from HLT through pump with 1.5" TC into MT. I can add cold, unfiltered water, but that's it.

[jebzter]

You are probably getting heat loss on the trip from the HLT to the MT, and as the HLT cools down, it becomes a problem. If your MT looses that much temp over an hour, I would think your HLT probably isn't faring much better.

[DageraadBen]

My guess is that the water in your HLT is stratifying by temperature. I'm going to guess that it's electric with both the heating element near the bottom of the tank and the temp probe higher up? If that's the case, your strike water might be a lot warmer near the bottom than the temp you're reading. This makes sense of the 3-4f temperature differential between your strike water and your target mash temp. I agree, I'd expect the differential to be more like 15f.

So here it is: your starting mash-in temp is closer to that 15f differential, but as the water level in the HLT sinks, your water gets cooler and cooler, and you miss your temperature.

The solution to this is to recirculate your HLT before you mash in, if you have a port you can go into near the top of the HLT. If you can pump water out of the bottom and into the top you can homogenize the water temperature and get a much truer reading on your temp probe. Then, at least, you can figure out what temperature differential you really need through trial and error.