Estimated Temp drop between HLT and Mash tun

Was not too sure if I should put this here or in equipment. Anyway here I go.

I have recently finished a single tier build. I have done two batches on it and both batches gave me a bit of trouble with temps. Here are the details:

• I heat my mash water in my boil kettle then transfer to my Mash Tun
  
• My system is hard plumbed with copper and PEX. Probably 5 feet of copper
  between BK and mash tun
• Bk and Mash tun are both converted kegs.

I used a brew calculator to try and determine the heat loss. I brought my water to about 175 and transferred to mash tun. After adding my grain the temp dropped to 134 degrees. This seems excessively low. I used a grain temp of 45 degrees in the calculator and my target temp was 155 degrees.

On my second run I had the heat exchanger finished and was able to bring the temp back up to where it was suppose to be, but it took a bit of time.

What should my next steps be for figuring this out. I would like to have this down before my next brew.

One thing I forgot to mention. After my last brew I got black pipe insulation. I think it is about 1 inch thick, and wrapped the copper tubing between the BK & MLT; also on the lines leading to and from the heat exchanger.

Why are you using 45*F grains? All that mass has to be heated somehow and results in your missed targets.

Why not rest the grains you will use at room temp?

Well mostly because I live in a really small townhome. The unheated garage is where I have room to store my grain. I live in colorado. Colorado is cold.

Okay. I get that but, why not measure out your grist and bring it inside for the night so you are infusing room temp grains?

All that I am getting at here is that in order for you to compensate the grain temp you have to ramp up the strike water and, while not entirely understood, there is concern and potential that doing so would "shock" the enzymes in the grain if not denature some or many of them prior to temp stabilization.

So, raise the temp of the grain and not the water.

45*F is cold bro.

Simply boost the temp of your mash water. I always go above what beersmith tells me. It's easier to stir out a couple of degrees than it is to add more water.

Well I was hoping for more complete solution to this issue. I have roomates and a swmbo who already see too much of my gear. In an ideal situation I could crush my grain then night before and set it inside the house. Reality is that it is a pain in the arse to get all my stuff off the loft and then put it all back. Move the car back in just to do it again the next day.

I would rather just do it all on brew day when the garage is cleared out and I have the time to dedicate to the process. It will be warm enough soon and I will not have to deal with that. But for a few months out of the year I should be able to figure out how to do with just raising the temp of the water.

Personally, I wouldn't even crush the grain the night before. Just bring in the amounts I will use the next day. If you strike was 174*F and you were 34*F short of target strike at dough-in you are likely going to be boiling strike water to hit target which may not happen due to system losses for not having a preheated tun or transfer piping.

You could also look into Colby's steam conditioning to raise the grain temp prior to dough-in.

Why not put your oven on 200 and pop in the grain for a few minutes?

Ok so warm the grain up. Then what? Should the calculators work correctly then? I still think I need an answer to "HOW DO I ESTIMATE MY TEMP DROP".

Sorry to be loud but my post does not say "method for warming my grain". I am looking for a solution to figuring out my situation as is. Even without the grain, the heat loss seems more then normal. I forget the exact number. Anyway. I guess I will just have to run a few batches of water again and figure it out through trial and error. I wrongly assumed I could use a formula to figure this out.

While I am in the Front Range, I have started out with grain at 45F.

I use BeerSmith to calculate the temps I need to use to hit my strike temp.

I pre-heat my mash tun with 175 F water for 10 minutes. I use a cooler and BeerSmith takes this into account. I pump the water back into the HLT and heat it back up temp for mash in.

While some people do just raise the temp to compensate. I feel the time spent raising the mash tun to temp is worth it. I have been able to hit my mash temps with no problem using 45F grain, pre-heating and BeerSmith calculations.

Brewmoor,

If you ever get down here to the flatlands on a weekend, send me a PM, I would be delighted to share some brews with you and show off my rig.

I've started out with grains at 35, calculated accordingly using BTP, and hit my temps just fine. I never thought of any issue with 'shocking' them due to temp but frankly this seems a bit silly. If shocking is an issue, I would think going from 75 to 150 would be a pretty hellacious shock already.
I think the OP has a fair question (to which I have no answer) and it doesn't have anything to do with warming his grains.

Wayne1 said:

While I am in the Front Range, I have started out with grain at 45F.

I use BeerSmith to calculate the temps I need to use to hit my strike temp.

I pre-heat my mash tun with 175 F water for 10 minutes. I use a cooler and BeerSmith takes this into account. I pump the water back into the HLT and heat it back up temp for mash in.

While some people do just raise the temp to compensate. I feel the time spent raising the mash tun to temp is worth it. I have been able to hit my mash temps with no problem using 45F grain, pre-heating and BeerSmith calculations.

Brewmoor,

If you ever get down here to the flatlands on a weekend, send me a PM, I would be delighted to share some brews with you and show off my rig.

Click to expand...

I will have to take you up on that. I get down that way every so often for work and fun.

As for pre heating my MLT.....I think that could be a good option. I have a 5 gallon corny with a coil in it for a heat exchanger. I could use that water to warm things up a bit. That would warm up the copper tubes and the mlt itself. Then use standard calcs. That might be ticket. Last time I brewed it was about 30 degrees in my garage. I had to keep the garage door open for most of the brewing because of all the steam and condensation. It sucked. Hopefully I can get a handle on it now that it is starting to warm up again. I am in eagle and we are now starting to get decent temps. Another few weeks and it will be a balmy 50 degrees on a regular basis.

I would pre heat the tun, add your water at what ever temp it's is and add cold water to bring it down to about 165F. Then add the grain in to the tun. A little flame to heat a little more cold water to cool. And stir like hell for the first 2 min because there is is going to be a big difference between top and bottom. Once you do it a few times you can very the 165 higher or lower to get it right on.

carp said:

I've started out with grains at 35, calculated accordingly using BTP, and hit my temps just fine. I never thought of any issue with 'shocking' them due to temp but frankly this seems a bit silly. If shocking is an issue, I would think going from 75 to 150 would be a pretty hellacious shock already.
I think the OP has a fair question (to which I have no answer) and it doesn't have anything to do with warming his grains.

Click to expand...

It's a scientific fact that if you exceed the heat limits for an enzyme you will denature that enzyme. Now, in consideration that only a fraction of the mash will contact the highly heated water before the mass stabilizes to a lower more reasonable temperature the term "shock" is used.

Yes, what you have to determine is the temperature loss due to heating the system. BeerSmith does estimate for this based on Thermal Mass of the system however, it only accounts for the tun itself and not the transfer piping system.

However, even if you did dial in the Thermal Mass of your system all BS is going to do is ramp up your strike water temps to compensate for the losses.

So, either you pre-heat your system or pre-heat your grain.

FWIW, in winter, I run a 60 watt incandescent bulb under my system in the garage to keep my system from freezing any potential residula water trapped in the plumbing or pump head. My system is also covered. I have noted that over the course of 48 hours that single bulb and the cover can trap enough heat to keep my system at a cozy 60*F even when temps are down to 10*F outside.

FYI, I forget wher it's located but there is a method to determine the thermal mass/heat loss of a sytem via infusions and time. IIRC, the ProMash brewboards have the method or a link to the method.

The book How to Brew has calculation that takes into account your grain temp. Put that in a spreadsheet and it will give you strike temp or close to it and your heat exchanger can do the rest

So lets say like in my last brew. I undershoot the estimate. I end up with a mash at about 140. What affect will it have on my beer if I use the heat exchanger to bring the mash up to the desired 155? Will conversion be affected?

I think I may try both ideas. Bring my grain in the night before and also maybe warm up the tun a bit too. I will just tell my roomates I am experimenting.

why dont you recirc until your about 10* above mash temps. Thats what I do for my RIMS setup. It will heat up the mash tun and all copper lines or my RIMS tube

Wow! so simple. Yet never crossed my mind to start recirculating before mashing in. I feel kinda dumb right now.

You rock my friend. This is precisely what I will do next go around. Thank you.

I've had the same problem on my last 2 (and only ) AG batches. I even went 5 degrees higher than the calculations said on the last batch and still came up 5 degrees short of my target. After reviewing the calculators I am wondering why ambient temperature or temperature of the mash tun is not taken into account. It seems to me that it should be included in the equation. If you know the temp of the grain and the specific heat of the mash tun why wouldn't you account for the starting temp? I may be totally off base here but I think as winter turns into spring and then summer I will hit my targets just because ambient temps will be up.

kryolla said:

why dont you recirc until your about 10* above mash temps. Thats what I do for my RIMS setup. It will heat up the mash tun and all copper lines or my RIMS tube

Click to expand...

Brewmoor said:

Wow! so simple. Yet never crossed my mind to start recirculating before mashing in. I feel kinda dumb right now.

You rock my friend. This is precisely what I will do next go around. Thank you.

Click to expand...

Aha. There you go. Sorry, I missed that you have a RIMS.

I dough-in cold, start the recirc, and direct fire heat to rest temp. And while I have no empiracle proof, I think my beers are better for it since I "drive by" all of the other rest temps. My pH is more stable/less extreme, haze is reduced, mashes lauter a bit easier, head retention is off the charts, etc.....

GilaMinumBeer said:

It's a scientific fact that if you exceed the heat limits for an enzyme you will denature that enzyme. Now, in consideration that only a fraction of the mash will contact the highly heated water before the mass stabilizes to a lower more reasonable temperature the term "shock" is used.

Click to expand...

I see what you mean by shock - you're not saying that the enzymes are affected by the large temperature change, but rather that the exposure to the hotter required water is the issue. I guess that makes sense, although the difference is pretty slight, say 173 vs 169 strike water, for grains at 65 vs 35.

Wellshooter said:

I've had the same problem on my last 2 (and only ) AG batches. I even went 5 degrees higher than the calculations said on the last batch and still came up 5 degrees short of my target. After reviewing the calculators I am wondering why ambient temperature or temperature of the mash tun is not taken into account. It seems to me that it should be included in the equation. If you know the temp of the grain and the specific heat of the mash tun why wouldn't you account for the starting temp? I may be totally off base here but I think as winter turns into spring and then summer I will hit my targets just because ambient temps will be up.

Click to expand...

Some software does take this into account, but first you have to perform some calibration to determine the heat capacity of your vessel. I think its just easier to preheat it, then its not an issue. For example if your strike water should be 169, put water at 172 into the MLT, let it sit and stabilize and cool down to 169, and then dough in.