Mash Temps

[VagabondBrew]

Hello Everyone,
First time poster long time reader. I've gotten into brewing this year (2011) and this fall we have moved into an all grain mash system.

We are currently using a 10 gallon cooler for the mash. My question is...
When we mash we boil the water to X, add it with the grain and becomes Y and then 30mins or more into the mash it is Z. The temp basically loses heat through X Y Z. When I am checking the temp I tend to note the initial temp after adding the grain and water which tends to be dead on or close to it but finding that end up losing heat later on.

Should I be worried about it still losing heat half way through the mash?

 

[fletchsj]

you really should try to keep temps as consistent as possible. I often kept my mash tun in the warm house covered in blankets during the winter due to heat loss. unfortunately without a way to heat it further you are stuck with limiting the heat loss to the best of your ability. In a cooler, you should, with blankets be able to keep it within a couple degrees. also, as long as you are getting complete conversion you should be fine.

Make sure you Preheat your MLT and keep it sealed up as much as possible for your mash time. IMO, it's more important to keep the heat in than to keep checking the temps. You might even try an electric heating pad if it's really cold out. But, be careful as h20 and electricity goes zap Good luck

 

[jetmac]

My process is to heat my strike water to a temperature above desired strike temperature, pour that into cooler, close lid. Keep checking temperature until it cools to desired temperature above strike temperature. Just as an example: heat strike water to 170F pour in cooler, close lid. Let cool to 166F. Then I dough in. And by the time I am finished doughing in I am pretty close to mash temp of 154F. And all the temperature loss is thru the grain addition not thru the cooler. I then close lid and wrap with an old comforter. At 15 or 20 min, I will stir and check temp. After an hour, I usually will wind up with mash starting 1 degree above mash temp then end 1 degree below mash temp. A couple degrees off won't really matter much.

As a side note, it's not always nessassary to go 1 hour on your mash.

 

[Clonefarmer]

What is your strike temp and how much does it drop to mash temp? With an unheated round 10 gallon I usually get about a 15 degree drop from strike to mash. The air temp, grain temp and batch size all have an effect on how much it drops. After that the temp usually only drops a degree or two at the most.

Are you opening the cooler repeatedly to check the temps? Every time you open the MLT some heat escapes.

Is the cooler well insulated? Check the cooler for hot spots during the mash. You should be able to feel if there is heat escaping through the cooler walls or lid. If there is heat escaping you can wrap a blanket around the cooler to help keep in the heat.

 

[Patrick604]

I use Beersmith2. I find this program to be spot on as far as strike temps for the mash. It will take into consideration the amount of grain, the grain temp, the cooler size, and the cooler temp and calculate the amount of water and the correct temperature to get your mash to the temp you want.

I take my 10 gallon round Home Depot cooler and put a couple of gallons of hot water in it for about 10 minutes or so while the strike water is heating. When my water is ready, I dump the cooler, pour my grain in, add the strike water from my pot and mix it up real good. Then I put my lid on it nice and tight and let the heat even out throughout the mash. I check the temp after 5 minutes and sure enough, it is right where Beersmith2 tells me it should be. I put the lid back on nice and tight and it holds the temp for an hour.

The only time I note a heat loss is when I go way beyond an hour for some reason, in which case it will drop a couple of degrees (3-5), and the initial loss from when the grain and water are added. This is all at ambient temps of 70-ish or above. I tend to brew inside when it gets cold out.

Using your terminology - do not worry about the heat loss from X to Y, this is normal and by heating your strike water above the mash temp you can compensate for this. All those grains and that plastic cooler suck the heat out of the water until everything stabilizes.

If you are experiencing temperature drops between Y and Z, your cooler isn't keeping the heat in. You are using the lid right? I've heard some people get different results with different style coolers. The one I use is a Home Depot rubbermaid cooler and works great. I can't speak for other brands or shapes . . .

 

[VagabondBrew]

We have been heating the strike water about 20 degrees higher. So lets say I was aiming for 154 mash temp, we get the water to 174. Add the water and grains and it tends to drop down to right around 154.
Sometime during the mash, normally halfway we'll open the lid and check the temp and find its dropped as much as 10 degrees in there and get somewhere in the 140's for temp

I will have to check for hot spots and look at wrapping it to see if that helps

The cooler was the 10 gallon mash system from northern brewer. We also pre heat it for about 10min before adding the grains and once the lid is on it only comes off maybe once during the mash. We also don't mash longer than 75min depending on style.

 

[insubordinateK]

Sometime during the mash, normally halfway we'll open the lid and check the temp and find its dropped as much as 10 degrees in there and get somewhere in the 140's for temp

wow 10 degrees? You have a problem. I use 10 gallon cooler from Lowes (rubbermaid) and noticed I was losing 3-4 degrees over the course of an hour. I drilled holes in the lid and filled with insulation foam (great stuff brand) and capped with plastic hardware. I find the temperature remains constant over an hour now. Last time I brewed in my garage, it was quite chilly as well.

 

[fletchsj]

Have you calibrated your Thermometer? That can be a big spot often over looked. When I first started all grain I was using a re purposed candi/meat thermometer type thing. I found out later (30+ batches) it ran cold and I was getting abnormally poor fermentation. I got a lot of really high final gravitys as a result.

also, where do you store your grain? I'm reaching... but if it is really cold due to being in the garage you might loose more temps there. I keep my grain in my brew closet so it's always about 60ish deg. Hope one of these suggestions helps.

If all else fails go buy a pump and dual purpose your immersion chiller and HLT into a HERMS

 

[VagabondBrew]

Have you calibrated your Thermometer? That can be a big spot often over looked. When I first started all grain I was using a re purposed candi/meat thermometer type thing. I found out later (30+ batches) it ran cold and I was getting abnormally poor fermentation. I got a lot of really high final gravitys as a result.

also, where do you store your grain? I'm reaching... but if it is really cold due to being in the garage you might loose more temps there. I keep my grain in my brew closet so it's always about 60ish deg. Hope one of these suggestions helps. )

The grain is normally between 60 - 70 degrees. I don't think it would be the Thermometer but worth a check. We just moved into a new location but this issue was happening before.

I'm looking forward to checking hot spots and seeing if wrapping it will help. I also have some insulation left I might play with to work towards better controlled temp.

We've just started brewing a good amount of beer rather regularly. We've done 65 gallons since Oct. Our 2nd to last batch had a high FG but pretty sure it was due to other issues. The current batch that's fermenting is still a little high after a couple days but plan on checking it on day 10 and hoping for the best. Overall the more I brew the more detailed I am becoming and more things I am noticing that I want to figure out why and how to change/fix =]

 

[insubordinateK]

Overall the more I brew the more detailed I am becoming and more things I am noticing that I want to figure out why and how to change/fix =]

Cheers to that, my friend.

 

[jetmac]

We have been heating the strike water about 20 degrees higher. So lets say I was aiming for 154 mash temp, we get the water to 174. Add the water and grains and it tends to drop down to right around 154.
Sometime during the mash, normally halfway we'll open the lid and check the temp and find its dropped as much as 10 degrees in there and get somewhere in the 140's for temp

I will have to check for hot spots and look at wrapping it to see if that helps

The cooler was the 10 gallon mash system from northern brewer. We also pre heat it for about 10min before adding the grains and once the lid is on it only comes off maybe once during the mash. We also don't mash longer than 75min depending on style.

I think I would get a refund on that cooler. If it loses 30F in a "pre-heated" cooler within 35min it must not be insulated.

When you open the lid about halfway thru your mash time, do you stir the grain?

 

[Rev2010]

Yeah that much loss isn't anywhere near normal. I have the same 10 gallon Rubbermaid mash tun and I only lose 1 degree or so over a full hour mash - and that is with opening it twice (20 minutes apart) to stir it up a bit.

However, I use Brewzor on my Android phone and Beersmith on my computer - they use the same calculator algorithms. That combined with a switch from a lab thermometer to this digital fast read one:

Amazon.com: RT600C Super-fast Water-resistant Digital Pocket Thermometer: Kitchen & Dining


has me always hitting temps perfectly. I stick the thermometer into my grains for about 10-15 seconds and read the temp and input the grain temp into the calc. I also preheat my mash tun with hot tap water and some boiling water from the tea kettle. Then I heat my strike water to the temp listed in the calculator and mash in and stir it up good.

But if you're having that much heat loss something else is up.


Rev.

 

[VagabondBrew]

We probably won't brew until early next year but I think I will take the cooler home and do some tests and maybe modify it a little. I have some ideas.

I think its a little late for returning it, we got it back in May. It's still useable but I think we can rig it to be a lot better.

Also I think I might look at picking up a thermometer or a similar model looks a lot better than the current one we use.

 

[artguy]

A couple of thoughts:

1. Run a no-grain, water-only test of the cooler. Pre-heat the cooler as you usually would, pour in water that has been heated to your desired mash temp (say 154F), close cooler, take a temp reading after 5 minutes to confirm a stable starting temp, then close for 30 minutes and measure again. If you've lost substantial temp, then you know it's a cooler problem.

2. Doing a normal mash as usual, mash in, stir like crazy, close cooler for 5 minutes, then open, stir and check temp again. Sometimes it is possible to get an inaccurate initial temp reading, before the heat exchange of mashing in has fully taken place.

Best'o'luck!

 

[kyleobie]

How deep does your thermometer go into the mash? I have noticed variation in my mash temperatures when I use a thermometer with a deep reach. The surface tends to cool quicker.

 

[VagabondBrew]

A couple of thoughts:

1. Run a no-grain, water-only test of the cooler. Pre-heat the cooler as you usually would, pour in water that has been heated to your desired mash temp (say 154F), close cooler, take a temp reading after 5 minutes to confirm a stable starting temp, then close for 30 minutes and measure again. If you've lost substantial temp, then you know it's a cooler problem.

Best'o'luck!

Planning on doing that this weekend =]