how quickly does your herms step up?

just to check my sanity... curious how quickly other peoples mashes in their herms step up.

doing my 2nd brew on the new rig and decided to do a step mash... for no other reason than... well.... i can.

while my HLT ramped up quick, mlt is about 10-15 minutes behind. it seems normal, but curious what other people are seeing. thanks for any experience notes guys.

 

Mine is about the same as yours 10-15.

 

I've struggled with this myself, and here's the theory behind the slow speed. The rate of temperature change is directly proportional to the difference in temperature between the two environments. Say, for example your HLT is full of boiling water, and your element is running full blast to basically keep it that way. If you pump 33* water through your HEX, it will come out at a fairly decent temperature - I'd wager in the mid 100's depending on the efficency of your coil. So you're experiencing at least a 100* change in temperature right off the bat. Pump that back into your original source, and the water will warm up very quickly. However, as the previously 33* water starts to warm up and get closer to 212*, the temperature change will slow and eventually stall damn close to 212, but not quite at it.

Where am I going with all this? If I'm doing a 10* step, I might set my HLT an extra 10-15* above my target temperature. This larger delta will increase the rate at which my mash heats up. The hard part that I haven't quite qotten down yet is when to reset the HLT temperature to my target temp, so that as the mash heats up, the HLT cools down, and I end up with exactly the temperature I want. I am curious if I reconfigure where my RTD monitors temperature, if it would be smart enough to do all the calculations for me and ramp up quickly without overshooting.

Short story - I have the same issues you guys have, just haven't figured out how to solve it yet.

 

A higher temperature differential will help, and so will a smaller heat exchange vessel because it will heat up and cool down faster. If you follow the logic through, you would use a counterflow chiller with the hot water flow in the jacket governed by a PID controlled pump. Another way to go might be steam injection.

 

well, at least im not nuts. the ratios others see are almost inline with mine.

i have ZERO complaints, i have a 14 G hlt with a 1/2" hex (see sig) and it works great....

just wrapping up brew two with close to 95% efficiency. my west coast brew buddy is crapping himself right now (i'm in NC) and can't believe my numbers...

all said, i'm curious on how quickly people are stepping and exchanging... im guessing if i didn't "clone kal" i'd use a smaller tube with quicker exchange but more variability...

 

Where are you in NC?

I'm currently working on an Electric Brewery with a 1/2" HERMS coil. I'll be interested to see what I see with my system.

 

Well, that is interesting. For any rest other than the saccrification rest, this probably won't be too bad, since the step ranges aren't nearly as tight as the saccrification rest requires.

 

Yes, I think that's true.

 

modo, i am in durham. where are you?

 

The main factors affecting the rate of temp ramp in your mash tun are thermal mass of the mash and flow rates thru your herms or rims. That assumes that you have adequate heating power in your HLT or rims. I had very rapid ramp ups when I was making 15 gallon batches and my HLT/herms had two 4500 watt elements. When I increased my batch size to 30 gallons, I could only use the HLT/herms to maintain temps during the mash. The rate limiting factor for me was rate of flow thru the herms coil relative to the size of the mash (thermal mass). The temp at the output of the herms coil comes up to set temp very quickly but the mash temp moves so slowly that it is not practical to do multistep mashes.

 

steve, im on 5500W but im suspecting that flow is a bit of an issue. working on that now...

 

I did some preliminary new testing on my 20 gal system just last brew, and rate of flow through my herms can change the temp at the mash inlet over 8 degrees. Too fast, and the temp will be too low, and if too slow, the temp will reach about 2 degrees below my HLT set point but take too long. I have not been able to get the heat loss through the pump and hoses less then 2 degrees from the HLT set point. I was going from 154 to 168 for mash out just using recirculation, and when I got my inlet set at a decent flow at about 4 degrees below my HLT set point (172), it took about 20 minutes to get there. I still haven't been able to crack above 85% efficiency, but I'm ok with that.

 

One thing you should be careful of for sacc. rests is your "over driven" temperature of the HERMS tank. If you want to hit 155°F mash temp and put your HERMS to 165°F, depending on your flow rate, you are essentially heating the wort to 165°C as it leaves the HERMS, even though the mash tun/grain bed is much lower in temperature. Overheating the wort by this much will change your desired outcome/fermentables. I suppose this isn't as big of a problem if you are just using the HERMS for mash-out.

 

I have one batch on my new system so take this for what it is... On my mash out I put the HLT temp to 175 and when my mash reading got to 165, I backed the HLT down to 170 and the 2 equalized out to 169. I will take a temp reading on the recirc port this weekend and see what the actual temp coming into the MLT is. The other thing I noticed on the first batch was that the MLT was about 2 degrees below the HLT most of the time. Maybe I need to increase my flow rate?

 

i never overdrove so to speak, so that isn't an issue. i actually ended up around 96% on this beer... it doesn't taste it, but a boozy 7% blond... ouch...

 

I'm not sure I agree here, though I'm also not smart enough on the biology and chemistry aspects to say for sure. Yes, you're heating a small amount of wort to a temperature above your target, which you are then quickly pumping back into a much larger container, essentially a heat sink, where the temperature will quickly be reduced back to the average. (Note - this all depends on flow speeds and recirculation rates etc, but the principal is the same).

What I'm getting at - are you really denaturing the enzymes by heating a small amount of wort over temp? Think about people who do decotion mashing, where they remove a portion and raise the temperature significantly... There's no issue.

The enzymatic action lies within the grains themselves, not within the wort. So heating the wort up will not shift you into different phases of the mash process. Only heating the entire mash and the grains will cause that to happen.

Thus, my belief is you can heat up the HLT above your target temperature and use that temperature differential to help raise the entire mash tun temperature.

Or, I'm full of it and someone can correct me... but I think I know what I'm talking about and I spent the night at a Holiday Inn...

-Kevin

 

Well, this could be possible. :cross: It was not my understanding that the enzymatic action was limited to the grain and not the wort.

At an instant in time you are only heating a "small amount" of wort to elevated temperatures, but over the course of mashing your entire volume of wort is likely going to pass through that HERMS at least once.

I'm not saying that this technique is going to produce "bad" beer, I'm just saying it will likely produce a wort with different fermentables than a simple infusion mash at the same temperature.

 

Yes , I do understand this. I can get to about a 2 degree difference with the correct flow and I'm measuring the temp at the inlet to my mash tun. The one thing I've been thinking though, is that although the HLT temp is higher, the wort entering is cooler and that not all the heat is transferred to the wort. It is dependent on the time the wort is traveling through the coil. So far I'm getting good results with expected final gravity if not being a little cautious and being a little over attenuated . I plan to shorten some of my hosing to diminish heat loss and hopefully pull temps closer. I agree that not paying careful attention to the process, I can overheat the wort traveling through the coil. I've done about 6 batches now on it and I'm starting to get a better feel for how the system reacts. Its so different from brewing 5 gallon biab on my stove, but I hope to really be able to dial it all in and get good consistency from batch to batch as I go forward and learn the system.

 

It's actually the other way around, the enzymes dissolve into the water. When you do a decoction you pull more grains than liquid for this very reason.

 

The "counterflow HERMS" idea was covered pretty informatively in this thread. It should definitely step up faster but the downside will be some denaturing as mentioned.

http://www.homebrewtalk.com/f51/herms-vs-counterflow-herms-349332/

Personally I reckon for most grain bills there should be plenty of diastatic power so the denaturing will not be much of an issue if the HLT temperature is within reasonable bounds. There will be a bit of trial and error and if denaturing gets to be an issue, just lower the HLT temperature. But that is totally off the top of my head, I have no experience with this kind of system.