Recirc for mash temp controlling?

[user 246304]

I tend not to recirculate during mashing, though I can. Mostly because I built my system only recently and the weather has been really cold. I can heat during recirc, of course, but bad memories from long ago when I built a keggle system and scorched the crap out of the bottom, I guess, leaves me sticking with a static mash. A few questions.

In the cold, do those with silicone hoses and Chugger-type pumps, as I have, it seems to me you're fighting heat dissipation in your hoses as much as in the tun. As the wort passes through your hosing and pump, you lose a ton of heat. What's your experience?

Another reason I've not heat recirculated, is that it seems to me you're denaturing the amylases (not to mention proteases, etc.) as you heat locally, are you not?

Finally, I have Spike vessels. I've felt that especially with something like this, even though I maintain a liquid pool floating on the grain bed, that whatever heat I might raise in the developing wort really doesn't penetrate through the mash bed efficiently, because the top recirc port is tangential. I actually cannot see how heated wort floated on top, however it's done, seeps uniformly through a large and deep grist. Your thoughts?

I don't step mash anymore, with the exception of a mashout. Just want to maintain a given mash temp. Last outing with the new system was terrible - nighttime, cold, and I was pretty shocked at not only how fast things dropped, but how much makeup boiling water I had to use to maintain the mash temp. Again, sort of paranoid of heating, I'm almost positive unwarranted.

Leaving me to say, seems to me I'm better off trying to nail insulation (saw a study somewhere, where of 4 methods, a simple sleeping bag worked best???) than heating to maintain temp. But I'm open to your thoughts. Thanks.

 

[RM-MN]

How long is your mash period, that time when conversion is happening? That is how long you need to have a stable temperature or nearly stable. We usually consider 60 minutes for mashing but does your mash really take that long to complete? What will happen to your sugar to dextrine ratio if your mash falls a degree or 2 while the mash completes?

 

[eric19312]

I have silicone hoses and chugger pump. Mash tun is bayou classic 15 gallon (much lighter than a spike kettle) with a Norcal false bottom. I recirculate constantly during mash over direct fire controlled by PID running a solenoid valve. I recirculate at about 1 GPM flow and never have had issue with scorched bottom. I did add a rotometer so I can keep an eye on the flow while doing other things just in case but only tend to have issues with grain bills with lots of flaked adjunctions.

No idea if holding mash temps rock solid is actually necessary. It makes me happy so I do it.

 

[user 246304]

How long is your mash period, that time when conversion is happening? That is how long you need to have a stable temperature or nearly stable. We usually consider 60 minutes for mashing but does your mash really take that long to complete? What will happen to your sugar to dextrine ratio if your mash falls a degree or 2 while the mash completes?

It depends on how much fermentability I'm seeking. My best bitter gets 90 minutes at 149, this strong bitter, 60 minutes at 151. I might get conversion at x minutes as indicated by iodine test, but I don't consider that "done," necessarily. And on the night in question, we were dropping from 149 to 140 or less, in 15 minutes. Crazy. Not wanting a complete beta honorific...!

 

[user 246304]

I have silicone hoses and chugger pump. Mash tun is bayou classic 15 gallon (much lighter than a spike kettle) with a Norcal false bottom. I recirculate constantly during mash over direct fire controlled by PID running a solenoid valve. I recirculate at about 1 GPM flow and never have had issue with scorched bottom. I did add a rotometer so I can keep an eye on the flow while doing other things just in case but only tend to have issues with grain bills with lots of flaked adjunctions.

No idea if holding mash temps rock solid is actually necessary. It makes me happy so I do it.

OK, good info, thanks, Eric. Not needing rock solid myself, but pretty concerned about losing 10 or more F every 15 minutes is a drag.

 

[mongoose33]

OK, good info, thanks, Eric. Not needing rock solid myself, but pretty concerned about losing 10 or more F every 15 minutes is a drag.

Losing that much temperature that fast is an insulation problem--or lack thereof. You could get some pipe insulation to put over the silicone hoses, could put a towel or some such over the pump head (not the motor part), and wrapping the mash tun better would also help.

Along the lines of that, and in case this gives you another idea....

...I use a 48-quart Igloo Cube cooler as a mash tun. In the past, when the garage temps are cold, I've taken the reptile heat mat I use for warming a fermenter and placed it under the cooler. I then wrap the cooler w/ a big blanket. The heat mat prevents heat loss through the bottom of the cooler and into the plywood on which it sits.

Makes me wonder if you couldn't get a heat lamp or floodlight or some such that threw off a lot of heat, and directed it at the bottom of your mash kettle. Or something similar that would provide supplementary heat that, along w/ better insulation, would allow you to maintain temps.

 

[user 246304]

Thanks Mongoose, that's a lot of great ideas. Funny you bring up the heat mat because I've got the final stage of a propagation downstairs in my former cheese cave. Cold right now, and only using the heating function of the Inkbird. It's only a 150 c.f. room but even that overwhelmed the little ceramic heater I have to heat it up to ferm temps (worked great in a refrigerator - my fermentors are too big so had to move downstairs). So I brought in a heating mat as supplementary heat and so far, it seems to be helping pull the room up to 63, which is about what I want at this stage of the ferment. We'll see for the rest.

Very helpful, thanks again.

 

[user 246304]

Mongoose, dumb question! But the hoses are from brewhardware, 1/2" ID, and they have the female camlocks on them. Would you go with 1/2" self seal insulation, or is there another size you go with, something like the 3/4" you linked to (we don't have Lowes unfortunately, but HD has similar stuff). Thanks.

 

[day_trippr]

[...]A few questions.

In the cold, do those with silicone hoses and Chugger-type pumps, as I have, it seems to me you're fighting heat dissipation in your hoses as much as in the tun. As the wort passes through your hosing and pump, you lose a ton of heat. What's your experience?

I brew indoors in a partially sub-grade unheated space that if it's 32°F outside will be around 60°F inside, so there's an admitted advantage there. In any case you've seen my rig and the 1/2" thickwall silicone run from my hex to my mlt is only about 18" in length. Given the radiating sheet metal surface area on a 20 gallon MLT (the whole reason for recirculation) the heat loss through that hose is mere noise.

Another reason I've not heat recirculated, is that it seems to me you're denaturing the amylases (not to mention proteases, etc.) as you heat locally, are you not?

I'm guessing that's more of a direct-fired MLT user question. I run my HLT ~1.5°F above the target mash temperature, and with 50 feet of 1/2" ss tubing the heating is pretty much the opposite of localized. I can't imagine a method less detrimental to beta amylase.

Finally, I have Spike vessels. I've felt that especially with something like this, even though I maintain a liquid pool floating on the grain bed, that whatever heat I might raise in the developing wort really doesn't penetrate through the mash bed efficiently, because the top recirc port is tangential. I actually cannot see how heated wort floated on top, however it's done, seeps uniformly through a large and deep grist. Your thoughts?

I recommend getting one of these or a similar thermometer and use it to check all around your MLT for temperature gradients while you go through the brew day. You may find you need to recirculate at a faster rate to hold the better volume of the MLT at the desired temperature. I have one and it helps me dial in my recirculation speed.

[...]Last outing with the new system was terrible - nighttime, cold, and I was pretty shocked at not only how fast things dropped, but how much makeup boiling water I had to use to maintain the mash temp. Again, sort of paranoid of heating, I'm almost positive unwarranted.

I've never run a direct-fired MLT rig but I can understand your reticence wrt cooking the wort, but I know folks do use DF MLTs successfully - though perhaps not in such cold conditions?

Leaving me to say, seems to me I'm better off trying to nail insulation (saw a study somewhere, where of 4 methods, a simple sleeping bag worked best???) than heating to maintain temp. But I'm open to your thoughts. Thanks.

Clearly, cutting thermal loss at the MLT is a huge process win when operating under adverse conditions but insulating a direct-fired MLT can be a challenge. I've seen all kinds of Reflectix implementations but always wondered why they didn't melt/burn at the bottom edges...

Cheers!

 

[Desert_Sky]

I turn pumps on after an hour for about 20 minutes. Thats when I can heat and not worry about scorching, but only to maintain temps. I dont use direct fire to mash out, only to maintain and initially heat the strike water.

 

[eric19312]

Direct fire mash is fine on enzymes so long as you maintain decent flow. My system is a DIY version of the Blichmann gas fired Tower of Power. I return the wort via Blichman autosparge, just a tube laying on top of the grain bed. I unscrew the float during recirculating then screw it back on when I switch over to lautering. Again direct fire recirc same as electric RIMS continuous flow is key.

I do step mashes frequently and have no problem ramping temps from 140 to 170 in the tun.

How do I know I’m not denaturing enzymes? First my mash full converts. Second I monitor temp in the recirc line. Right after the pump. Controller kills the flame when recirc hits set temp. Comes back on half a degree below that.

I brew in a garage, it does get pretty cold but probably not below 50 on a brew day and I use natural gas so I can brew doors closed if needed. Actually that natural gas might be related to my direct fire success...good constant recirc rate and low flame. You don’t want to be hitting that mash tun with high pressure propane 14” banjo on full blast...that might risk scorching or denaturing.

 

[schematix]

120V electric RIMS is what you need.

 

[user 246304]

Thanks everyone, ton of information and ton of help. I need to chew on this stuff. At the moment I and mother nature aren't the best of friends. Absolutely dumping on us with snow. Snow! I had a window to brew and have been working up a Yorkshire yeast in the square fermentor I got from a good man on this site, and was looking forward to hitting a strong bitter. Then this white crap is nailing us. I go into surgery Tuesday morning so it's going to be - shock and horror! - a couple weeks (hope!) before I can probably brew. Don'cha hate it when you're itching to brew, and for whatever reason, you can't?

Takeaways. Yes, electric, inside, just took a serious "what the hell was I thinking" bounce. And like Eric, so has natural gas, but I have none in the garage. So it's propane, hellfire banjos, outside, you know - where it's dry, sunny and 151F all the live-long day.

Thank you again, everyone. I'll be sitting with your ideas.

 

[acidrain]

HERMS over RIMS for the win.

 

[user 246304]

HERMS over RIMS for the win.

I suppose I'm going to have to learn the difference now.

I'm stubborn as a mule in finding a way to insulate the tun adequately. Here's that article I mentioned guys, compares 4 different ways to insulate the mashing system (it's based on a Brewer's Edge Mash and Boil, which the author says has a 6 degree swing). The stock kettle, Duck Brand Water Heater Insulation, Reflectix, Cold-Weather Sleeping Bag. Nominally gives the win to the sleeping bag, of all things, though there's an interesting discussion on practicalities. I recall now that on my system from long ago, I had water heater insulation just duct taped on to the mash tun. It was truly ugly, but worked pretty well. I need something, for sure.

 

[TenaCJed]

I went with RIMS myself, but you need to find a way to help stabilize and maintain the temperature you want.

 

[schematix]

Only advantage to HERMS is you can guarantee your wort won't see hot spots like you will in a RIMS since the recirc loop gets its heat from the HLT water. Other than that it's more equipment, more cost, more water to heat and slower to react.

 

[user 246304]

OK, thanks for the explanation guys. Kind of ridiculous I honestly didn't know the difference. Never been anything but a direct fire guy, which obviously has its limitations.

 

[mongoose33]

Mongoose, dumb question! But the hoses are from brewhardware, 1/2" ID, and they have the female camlocks on them. Would you go with 1/2" self seal insulation, or is there another size you go with, something like the 3/4" you linked to (we don't have Lowes unfortunately, but HD has similar stuff). Thanks.

It doesn't really matter what kind you use as long as you cover most of the hoses. You're losing heat at the pump and fittings as well as around and on top of the mash tun. All you're trying to do is limit heat loss to an acceptable level. I just offered up the pipe insulation as a cheap and easy way to manage that.

I'd get something that can be easily removed if and as necessary. Even if it doesn't seal completely around the hoses, it'll cover most of it. The more important issue is getting pipe insulation the same size as the hoses, as then it will insulate most of that hose directly. If a little opening exists in the insulation, it's still only a small fraction of what is exposed with no insulation.

Another thing you could do is to shorten the hoses if you can. You're just trying to limit heat loss exposure to ambient conditions.

 

[schematix]

OK, thanks for the explanation guys. Kind of ridiculous I honestly didn't know the difference. Never been anything but a direct fire guy, which obviously has its limitations.

Both methods recirculate.

The difference:
-HERMS heats wort by recirculating through a Heat Exchanger (typically a coil in the HLT, but other methods are possible)
-RIMS recirculates wort past a heating element in a canister.

Since the surface area of the heating element is so much smaller than the surface area of a coil, you get higher localized heating.

 

[user 246304]

It doesn't really matter what kind you use as long as you cover most of the hoses. You're losing heat at the pump and fittings as well as around and on top of the mash tun. All you're trying to do is limit heat loss to an acceptable level. I just offered up the pipe insulation as a cheap and easy way to manage that.

I'd get something that can be easily removed if and as necessary. Even if it doesn't seal completely around the hoses, it'll cover most of it. The more important issue is getting pipe insulation the same size as the hoses, as then it will insulate most of that hose directly. If a little opening exists in the insulation, it's still only a small fraction of what is exposed with no insulation.

Another thing you could do is to shorten the hoses if you can. You're just trying to limit heat loss exposure to ambient conditions.

Thanks Mongoose. Yeah, I'm asking what size foam insulation do you get, if you have 1/2 ID silicone hose (I know it's stupid. I just don't know what OD Bobby's hosing is).

And thanks for the note on the hose length. Mine are ridiculously overlong. I was ahead of myself and based the length on other companies, and the estimate of what I'd need when everything was done. I actually have to do a folding act using the thermos or valves to hold the hosing while brewing. It sucks, and I just haven't gotten around to cutting them. Each could easily lose at least a foot, I'd imagine, with at least 1 or 2, losing more. Dumb laziness.

Thanks again. I think I'll try something on the mash tun that I'm comfortable using while firing, i.e., heating strike water (unless I just use the HLT).

 

[user 246304]

Both methods recirculate.

The difference:
-HERMS heats wort by recirculating through a Heat Exchanger (typically a coil in the HLT, but other methods are possible)
-RIMS recirculates wort past a heating element in a canister.

Since the surface area of the heating element is so much smaller than the surface area of a coil, you get higher localized heating.

OK great, thanks, schematix. I was around when RIMS first came out and my memory was that there were some issue with localized heat. I have no idea what changes have been made, but I'm sure their substantial.

Simply didn't know. It does have me thinking.

 

[schematix]

OK great, thanks, schematix. I was around when RIMS first came out and my memory was that there were some issue with localized heat. I have no idea what changes have been made, but I'm sure their substantial.

Simply didn't know. It does have me thinking.

Yah a lot of early RIMS used standard high density water heater elements. These days there are a lot of ultra low watt density elements, or better, in use. Scorching doesn't have to be an issue, but it's a possibility if you stop flow.

 

[user 246304]

Yah a lot of early RIMS used standard high density water heater elements. These days there are a lot of ultra low watt density elements, or better, in use. Scorching doesn't have to be an issue, but it's a possibility if you stop flow.

Interesting, thanks, schematix.