Inverted HERMS? (iHerms)

**Denny's Evil Concoctions** · 04-06-2009, 11:49 PM

I've been toying with the idea of doing what I call an Inverted HERMS (iHERMS? lol).

You recirculate your mash liquid but it does not go though the HLT. It just recirculates from the bottom of the MLT to the top. There is a coil in the MLT that hot water is pumped through.

My theory here is that it would provide more equal heating of the mash and allow for better step ups in temperature in the mash.

It would require an additional pump for the hot water, but not necessarily food grade if the water was heated separately from your HLT. (If using your HLT as the water source then you would want a food grade pump).

Has anyone done this? Thoughts?

I probably won't get around to doing this for a while. I've already spent to much on things lately.

The Pol · 04-07-2009, 01:07 AM

I will have to disagree with the thinking that this will somehow allow faster step ups in the MLT. How? You are still heating the same ammount of liquid arent you. The liquid in the HLT and MLT? You are still using the same heat source arent you? Thusly... the same BTU, same volume, same time.

As for more uniform heating Id say again, maybe not. Even though you are recirculating the MLT water, you will have a direct source of heat in the MLT, creating relative hot spots near the coil. In a true HERMS, you dont have this, there is no heat source in the MLT, more uniform heating.

So I dont see any real gain, but I do see the expense of another pump.

My thoughts, my .02.

**Denny's Evil Concoctions** · 04-07-2009, 01:17 AM

Well, it has been argued that the mash from a HERMS tends to be hotter at the top. The coils won't be any hotter than the water source so I don't really see the difference in relation to a HERMS.

You set the water source at your target temp not above it. This is still a heat exchanger. I didn't say it would necessarily be quicker. Just a more even rise in overall mash temp through out the entire mash.

The Pol · 04-07-2009, 01:21 AM

I understand the concept of HERMS... I just figure that if you are pumping at a rate of 1.5 gal/min, you are recirculating the entire mash every 2-3 minutes. If your vessel is insulated at all, the ammount of heat lost from top to bottom in a 2-3 minute period would be minimal. The re-heated mash water entering at the top would be the same as your target temp, as you stated. So, unless it is cooling significantly during its 2-3 minute trip to the bottom of the MLT... I dont see the issue with temp stratification in the MLT with a typical HERMS.

You did state in the OP that youd expect to be able to step temps better... that is what I referred to in my previous post. I presumed better meant faster.

The Pol · 04-07-2009, 01:32 AM

Not trying to talk you out of it... I say do it. I dont know that there will be any difference in the quality of the beer, but it definately wont hurt it. I am just the type that doesnt want to buy another piece of equipment unless the cost/benefit ratio is there somewhere.

**Denny's Evil Concoctions** · 04-07-2009, 01:45 AM

This is what I'm trying to determine. I've read some pretty valid arguments against using HERMS for step mashes due to the stratification of the mash.

This shouldn't happen with this type of system when raising temps. The entire mash should be rising in temp at pretty much the same time.

Also, besides what I have read, I noticed something the other day when I decided to do a batch sparge for once.

I mashed out at 170. Drained then filled the tun with the sparge water and recirculated for 15 minutes. I didn't stir the mash at all. I used a 180F sparge since I noticed the temp on the tun had dropped to around 165F. (keggle MLT and it was pretty cold out).

The temp on the tun after recirculating for 15 minutes was about 170F. When I stopped recirc and drained the tun I noticed the MLT temp started climbing till it hit close to 180F. There was definitely stratification going on. (Therm is near the bottom of tun). Even though this was aprge water, this should be close to the action of a HERMS when raising temps.

Maybe this is less of an issue with a cooler MLT? I dunno.

I was going to change to a HERMS but I keep reading that they aren't very good for step mashes and I do have some recipes I like to do step mashes with.

BTW, I'm not declaring this to be the best or better system. I'm just theorizing and asking for discussion upon the merits of such a system; particularly in regards to step mashing. Is it worth the expense of another pump? Would it really work any better?

(note: above temps are approximate. I forgot to write them down, and I'm going from memory.)

The Pol · 04-07-2009, 01:55 AM

#1... HERMS is horrible for step mashing... there is no way to make it work. Since you cannot heat the wort in excess of the target temp, it takes forever, I have a special spreadsheet made for my system so that I can couple recirculating with infusion mashing all from the same HLT water.

#2... When I mash out, I recirculate for about 20 minutes (this is the only time I use HERMS to step up the mash temp)... after 20 minutes I dont see any stratification in the temps in the cooler.

#3... I DO think that coolers make a huge difference. I mean they have lids and an inch of dense insulation on the sides and bottom. There is so much heat lost with SS and aluminum kettles, that compeltely changes the variables. If it is 40F outside, my cooler shell is 40F... there is no heat loss. A SS kettle wall would be about the same temp as the mash... A LOT of heat loss.

**BierMuncher** · 04-07-2009, 02:02 AM

#4....I've no idea what you guys are talking about...but it sounds like fun.

#E....I like bullet pointing for emphasis too...

#6....What were we talking about????

The Pol · 04-07-2009, 02:05 AM

Quote:

Originally Posted by BierMuncher

#4....I've no idea what you guys are talking about...but it sounds like fun.

#E....I like bullet pointing for emphasis too...

#6....What were we talking about????

Psst, someone is drinking.

**Denny's Evil Concoctions** · 04-07-2009, 02:13 AM

Quote:

Originally Posted by The Pol

Psst, someone is drinking.

No, that's just Biermuncher's educated input into the discussion.

... Nah, he's druk.

Pol, I'll have to give this some more thought. I don't really want to get another pump, and I do want to be able to step mash. My Keggles are all insulated but are no where near as heat keeping as a cooler.

I've had two scorches trying to step up with a direct fired RIMS. I don't like the idea of overheating the wort (standard RIMS). Hmm... Somehow there has to be another way..