Heated Mash Tun?

[derfburg]

I saw this on BYO and thought how easy it would be. Would this work or just go HERMS?

http://byo.com/component/resource/artic ... n-projects

[Bugeater]

In my opinion, this is a solution in search of a problem. If you are having excessive heat loss in your mash tun, you need better insulation or mash someplace warm. But then again I am a lazy SOB and am happy with my cooler mash tun and doing the mash in my kitchen.

If you are enamored with the gadgetry, go for it. One thing to keep in mind is that to keep the temperatures even, you will still need to stir. I saw an article in BYO several years ago about converting either an ice cream freezer motor or a BBQ spit motor to slowly rotate a mash paddle. I think Dan Listerman built one once.

Stop and think before you build. Will it help you make better beer? Will this make enough of a difference in temperature control to justify cleaning more gear each time? Will it shorten your brew day? These are the questions I consider before trying a new gadget. If you are a gadget freak and want to build it for the enjoyment of building it, by all means do it and post some pictures. This kind of construction is fun even if you decide later it is too much trouble to actually use on a regular basis. (I have a couple items like that.)



Wayne

[Ozwald]

In my opinion, this is a solution in search of a problem. ... If you are a gadget freak and want to build it for the enjoyment of building it, by all means do it and post some pictures. This kind of construction is fun even if you decide later it is too much trouble to actually use on a regular basis. (I have a couple items like that.)

+1 to this.

It's nothing but a backwards HERMS system. I'd also like to point out a big mistake in the article where he didn't want to go RIMS since he'd have to pump hot wort for an hour. RIMS & HERMS are nearly identical ideas. With my HERMS system, I have never ran the pump for an hour. Or even half of an hour. You typically only need to circulate to ramp up. It's pretty amazing how much thermal mass your mash actually has & even in these cold Montana winter brewdays it'll keep pretty stable. I've had to turn the pump on for a few minutes mid-mash cause I lost a degree, but only cause I could. Pre-HERMS, big deal, it was 1 degree 45 minutes into the mash. I am waiting for my new Blichmann mashtun to show up today, so perhaps moving from a cooler to a stainless vessel might require a bit more recirc, but if it's anything more than a few minutes I'll just get some extra insulation.

As someone who likes to build stuff, it looks like a fun project that would get used exactly once. If you do decide to build it, definitely post some pics of the build & a brew on it. It would definitely be interesting to see.

[derfburg]

Since I posted this I have a new option come about. A friend of mine has a Tower of Power Module (no tower or pump, just one) that was a impulse buy for his shop. Never used or even opened. He is going to let me use it into my system in exchange for some brewing time.

That said, I am going to just use it as a HERMS system with my existing pump, and wort chiller. I already do a small recirc after mash in to set the temp and grain bed, so all holes and plumbing is there. Right now I use a cooler for my MT, so it will not have HUGE swings in temps, but would be nice to have better control. Plus it is basically free.

All that will need to be done is figure out where to put the Temp probe for this bad boy. Right before the wort flows back into the MT? I could do a contentious recirc since it has the gas valves and auto light feature.

[Ozwald]

Since I posted this I have a new option come about. A friend of mine has a Tower of Power Module (no tower or pump, just one) that was a impulse buy for his shop. Never used or even opened. He is going to let me use it into my system in exchange for some brewing time.

That said, I am going to just use it as a HERMS system with my existing pump, and wort chiller. I already do a small recirc after mash in to set the temp and grain bed, so all holes and plumbing is there. Right now I use a cooler for my MT, so it will not have HUGE swings in temps, but would be nice to have better control. Plus it is basically free.

All that will need to be done is figure out where to put the Temp probe for this bad boy. Right before the wort flows back into the MT? I could do a contentious recirc since it has the gas valves and auto light feature.

Nice score, those things ain't cheap!

As for the temp probe, measure the wort leaving the MLT or the grain bed itself.

[derfburg]

As it exits the MLT? Hmmm just curious of reason? Like to know when I am asked later.

[Bugeater]

I understand you concern about where to measure the wort temperature. The problem I see is that by measuring in only one spot, you don't know if you have cold or hot spots elsewhere in your mash tun. Even after I have stirred for a bit, I sometimes notice 4°-5° temperature differences when I check the temps in various places. This is how I know to stir some more. When you are recirculating, how do you know that you are getting to all the corners evenly? You do need to check with a long stem probe in addition to using a fixed placement at the beginning of the mash to make sure you don't have those hot/cold spots. You can get away with placing the fixed probe pretty much anywhere. Once you figure out what overall mash temperature you get from a given temperature at your fixed probe, you can adjust your herms setup to compensate for any difference.

[Ozwald]

As it exits the MLT? Hmmm just curious of reason? Like to know when I am asked later.

Just something I learned from experience. I ran 3 thermometers off my old MLT, a send, return & main mash body.

The return isn't going to tell you a whole lot. You can make estimates about how much longer before your main mash temp hits it's target, but you can see that on the other 2 thermometers as well. When you recirc, it's a pretty slow process - if you move the wort through the exchanger too fast, it won't heat up all the way & it's actually going to take longer. At a slow ramp/flow rate, you're not going to have the hot/cold spots that Boog mentioned at all (provided you're not channeling). Estimating from the volume of my exchanger loop & flow rate, I would estimate during a ramp from 153 to 168, the entire volume of liquid will pass through the exchanger about 5-6 times. It's a very even way of heating the mash.

As for measuring the main mash vs the MLT output, they're going to be very close with the output lagging ever so slightly. I'm sure that a main mash body temp would be sufficient, but making the output temp catch up tells me that the main mash is, in fact, all the same temperature. Several double & triple checks have confirmed this.

Each HERMS exchanger is going to operate a little differently. Mine happens to be at a 10 degree offset. If I want the returning liquid to be at 170, I hold the HLT at 180. I don't change the HLT temp during the ramp at all. Set it to target+10 & let her go. The mash will ramp fairly quickly at first & then slow way down. It takes longer to go from 167 to 168 than it does to go from 153 to 160. This is also how you get the mash output temp catch up to the main body.

Having 3 thermometers helped me learn a ton about my system & how it operates, but the return thermometer really isn't that helpful after you figure out the HLT offset. It certainly won't provide any information on what's going on in your mash as it's just going to read an offset of your HLT the entire time. Hell, if you figure out the offset, you can tell your return temp to the degree just by looking at the HLT temp. I just retired that old MLT & am putting a bigger & nicer one into play. It's a Blichmann BoilerMaker & I'm not adding any thermometers besides the one that came with it (which is measuring mash body). I wouldn't have gone this route on my first build, but now that I've worked with HERMS enough I'm comfortable estimating the output/return temps from experience.

Another note after rereading everything, note that you cannot put the probe just about anywhere & expect reliable readings with a HERMS system. If you're measuring the main mash body, you'll want to be below the half-way point. Too close to the top, you'll never get an accurate reading. I like it 1/3 up from the bottom.