HERMS Temperature - Too Hot?

[MaplePaddle]

I’ve been having issues with low attenuation on my dark brews. I’ve scrutinized my process and I’m now thinking the source of my pain is recirculation temp. It’s important to note, due to technical limitations of my propane set up, I only recirculate my wort when I add heat. Also, I stir to ensure even and quick distribution of heat.

Question; Has anyone experienced high quantities of unfermentables, while processing dark wort, if HERMS runs too hot? I currently recirculate with my heat exchanger coil in a 200F water bath. Again, this is done intermittently with constant stirring only when adding heat. A typical step mash programme would be 60min@144F, 30min@150F, 10min@168F. FG of my dark brews are finishing 6 to 14 points higher than anticipated. My OGs are within 2 points of target.

 

[jekeane]

You would need to check the temperature of the wort output as it returns to the mash. I would assume you are denaturing enzymes as you run through the coil at 200°

If your return wort is coming out in the 160 range to everything in the wort is getting less fermentable.

I used to for the sake of time when ramping heat my hlt way above my desired temp. When I did that I would be consistently under attenuated.

 

[Smellyglove]

There are several people around the web which has done this, recirculating at a high temp in the HEX, and reported back poor attenuation.

Ideally you shouldn't overshoot the mash-temp at all, a short period of low overshoots are (in my experience) ok.

You are denaturing the Beta amylase-enzymes pretty quickly.

 

[MaplePaddle]

I’ll have to try lowering the temp. Puzzling that it has no noticeable effect on wort SRM <10. Only darker brews >20.

 

[day_trippr]

My 50' 1/2" SS hex holds just over 2 quarts/1.93 liters of liquid.
If you have a similar hex you're denaturing that much wort every time you stop your recirculation.

I wonder if the lighter recipes simply convert before you've had a chance to whack them...

Cheers!

 

[MaplePaddle]

My 50' 1/2" SS hex holds just over 2 quarts/1.93 liters of liquid.

If you have a similar hex you're denaturing that much wort every time you stop your recirculation.



I wonder if the lighter recipes simply convert before you've had a chance to whack them...



Cheers!

I think your point has merit, so I checked my notes. I have an insulated mash tun, so I only had to recirculate on each occasion for 30 seconds at 30 minutes, 2 minutes at 1 hour, and 10 minutes at mash out. Therefore maximum 4 quarts of wort (out of 24) would have been denatured, ignoring the last temperature rise as it was my mash out. The 4 quarts doesn’t seem proportional to the effect.

 

[MaplePaddle]

There are several people around the web which has done this, recirculating at a high temp in the HEX, and reported back poor attenuation.

Ideally you shouldn't overshoot the mash-temp at all, a short period of low overshoots are (in my experience) ok.

You are denaturing the Beta amylase-enzymes pretty quickly.

I checked my notes and my mash temps never overshot my targets. My recirculation are momentary, only to add temperature. I use an insulated mash tun. 30seconds@30min and 2min@60min.

 

[day_trippr]

[...] Therefore maximum 4 quarts of wort (out of 24) would have been denatured, ignoring the last temperature rise as it was my mash out. The 4 quarts doesn’t seem proportional to the effect.

Can't argue with your conclusion.

So, next question: what is the actual temperature of the wort exiting the HEX when you are circulating?

Cheers!

 

[MaplePaddle]

Can't argue with your conclusion.



So, next question: what is the actual temperature of the wort exiting the HEX when you are circulating?



Cheers!

Approximately 185F

 

[day_trippr]

Woof. That can't be good.
Time to reconsider your strategy, imo...

Cheers!

 

[LarMoeCur]

Where is your temp probe in the Mash tun? If your dumping 185F wort on top of the grain bed and taking the reading at the bottom you are denaturing way more than 4 quarts. The beta enzymes denature significantly past 149F. So any wort left in the coil is for sure denatured and I'd bet that any wort running through the 200F coil is denatured before it exits the coil. Most HB pumps run about 7 GPM so 3.5 gallons per 30 seconds is being denatured more than half of the mash. Your are flash pasturing your wort. I'll bet you are extracting tannins as well.

Next why are you doing a 90 minute mash? Unless your using a ton of under modified malts. Almost all the conversion was completed in the first 60 minutes. There are brewers who swear by a 30 minute mash. I've read studies that say 80% of conversion happens in the first 10 minutes.

Why not set the HLT 2 degrees above your mash temp and run the recalculation the entire mash time? If your dead set on that schedule, I'd mash at 144F for 30 minutes, ramp up to 150F for 20, and then 168F for 10. Or just mash at 148F for 60 and mash out at 168F for 10.

 

[MaplePaddle]

I’ll make some changes. Thank you all

 

[acidrain]

I think most folks (me included) use a lower kettle temperature and recirculate constantly.
I set my kettle temp only a few degrees higher than my target mash temp.
Why is your kettle temp so high? Fly sparging?
Consider batch sparging... it's much faster.

 

[MaplePaddle]

I think most folks (me included) use a lower kettle temperature and recirculate constantly.

I set my kettle temp only a few degrees higher than my target mash temp.

Why is your kettle temp so high? Fly sparging?

Consider batch sparging... it's much faster.

Step mashing. I found it took way too long to get my mash out temp to reach 170F if my heat exchanger was below 190F when I started to raise the temp. Created another problem I guess.

 

[doug293cz]

Step mashing. I found it took way too long to get my mash out temp to reach 170F if my heat exchanger was below 190F when I started to raise the temp. Created another problem I guess.

It's not worth killing your mash to do a mash out. much better to skip the mashout, and get good results out of your mash. You could switch to batch sparge, in which case a mashout is not particularly useful.

Brew on

 

[metaltim]

I have my HLT at about 170. Mash surprisingly holds temp well for being just an open top ss pot. The HLT is below the mash tun on my stand, so it puts off a lot of heat which helps keep the mash tun warm.

Then about the last 15-20 minutes of sacc rest I fire up HLT burner to get HLT to 185 (again, which helps the mash tun keep its temp). By the time it gets there, it's time to mash out, so I fire up pump and getting the mash to 165-170 is easy, about 10 minutes or so. I think you found your problem; keeping HLT at 200. That is really hot.

 

[devils4ever]

Approximately 185F

Yeah, I think that will cause problems.

I keep my pump running the entire mash process and use a temperature probe and controller to keep the mash temperature constant. I usually need to set my kettle with the heat exchanger in it (SS coil) about 1-2F above the mash temperature.