Effects of losing temperature during mash

[E_Rock]

Last weekend I brewed my first BIAB batch, a Cream Ale. After throughly stirring in the grain, my initial temperature was 154F. I put the lid on and covered the kettle with 2 fleece blankets. Every 15min, I uncovered, stirred and took the temp with my thermapen.

:00 - 154F
:15 - 152F
:30 - 150.5F
:45 - 149.7
:60 - 147.2

average - 150.7

I wanted to keep things simple and didn't want to add additional water to keep the temp steady, nor did I want to take the chance of melting the bag by firing the blichman back up. My goal was to mash at 151F, so if I use the average temp, I suppose I hit it. Obviously, I started out higher than I should have, but I was eager to get going and let it cool down a little more. I used some calculators, but wasn't exactly sure how much I would lose be adding the grains. (It was about 157F before adding grain.)

I suppose I am not really sure what my question is, just looking for some general feedback. I hit 75% efficiency which seems pretty good for a first attempt. I've read different information that a lot of the conversion happens early on, so perhaps I should consider my mash temp to be higher than 151? I'm just trying to understand so I can use this knowledge to plan future batches. The next go around I plan to build a reflectix jacket, assuming that will be a better insulator than 2 fleece blankets.

 

[Yooper]

I bet if you just kept it covered and didn't open so often to stir and check the temperature, it would have held the proper temperature for longer.

Conversion tends to happen pretty fast with today's well-modified malts, but using adjuncts like corn and rice can sometimes means it takes a bit longer to convert. Often, a barley malt mash will be converted in 20 minutes. In other words (I tend to ramble on, sorry!), it was fine. but next time, stir well at dough-in, and stir again. Stir some more, make sure there are no doughballs and that the mash is the same temperature throughout, and then cover it well and walk away.

You can check the temperature at the end of the mash, instead of three or four times, and I am willing to bet you will lose less than 5 degrees.

 

[Denny]

I bet if you just kept it covered and didn't open so often to stir and check the temperature, it would have held the proper temperature for longer.

Conversion tends to happen pretty fast with today's well-modified malts, but using adjuncts like corn and rice can sometimes means it takes a bit longer to convert. Often, a barley malt mash will be converted in 20 minutes. In other words (I tend to ramble on, sorry!), it was fine. but next time, stir well at dough-in, and stir again. Stir some more, make sure there are no doughballs and that the mash is the same temperature throughout, and then cover it well and walk away.

You can check the temperature at the end of the mash, instead of three or four times, and I am willing to bet you will lose less than 5 degrees.

THIS^^^^ I close my cooler and let it sit for 60-90 min. and never lose more than 1-2 F.

 

[E_Rock]

I bet if you just kept it covered and didn't open so often to stir and check the temperature, it would have held the proper temperature for longer.

Conversion tends to happen pretty fast with today's well-modified malts, but using adjuncts like corn and rice can sometimes means it takes a bit longer to convert. Often, a barley malt mash will be converted in 20 minutes. In other words (I tend to ramble on, sorry!), it was fine. but next time, stir well at dough-in, and stir again. Stir some more, make sure there are no doughballs and that the mash is the same temperature throughout, and then cover it well and walk away.

You can check the temperature at the end of the mash, instead of three or four times, and I am willing to bet you will lose less than 5 degrees.

This makes so much sense. I guess I was under the impression that I had to keep stirring it throughout. If I can just do a good job up front and walk away, all the better! I will certainly give that a shot next go around. Thanks!

 

[brandonnys]

Yeah, just leave it closed. If you want to monitor the temp, install a thermowell or something so that you don't have to open the lid.

However, the effects of opening the lid in your case may better activate any beta-amylase that hasn't already denatured, giving you a more fermentable wort.

 

[Apple_Jacker]

I just brewed some beer on Sunday. My mash temp target was 150 degrees. I stirred the hell out of the grains/mash, placed a temperature probe in the middle of the mash, covered the kettle with 4 or 5 towels, and started the 60 minute countdown. I opened to stir at the 20 minute mark and again at the 40 minute mark (twice during the 60 minutes). I lost only 1 degree over that time period.

 

[JayInAmes]

I am trying to track down efficiency issues. First all grain was 61%, next one was 65%. The latest one was 71%, and I've been keeping the temperature right at the mash temp. The 71% was mashed 10 mins longer, and I decocted it twice to keep it at 151 (it had dropped to 149 at 50 mins). Should I not worry about that temp drop? Since it was at the lower end of mash temps, I thought I should keep it up.

Meanwhile I've drilled holes in the manifold and evened out the slots, hoping to get some more points of efficiency. I guess I was putting a lot of emphasis on temp control, is that misplaced emphasis?

 

[jerbrew]

I am trying to track down efficiency issues. First all grain was 61%, next one was 65%. The latest one was 71%, and I've been keeping the temperature right at the mash temp. The 71% was mashed 10 mins longer, and I decocted it twice to keep it at 151 (it had dropped to 149 at 50 mins). Should I not worry about that temp drop? Since it was at the lower end of mash temps, I thought I should keep it up.

Meanwhile I've drilled holes in the manifold and evened out the slots, hoping to get some more points of efficiency. I guess I was putting a lot of emphasis on temp control, is that misplaced emphasis?

In regards to efficiency? Probably. It really depends on what efficiency you're talking about and making sure you know exactly what you're measuring. Brewhouse efficiency of 71% or a pre-boil efficiency of 71%? you need accurate gravity and volume measurement throughout your process to really track down where you losing juicy little sugars. If you're getting 71% brewhouse that's really not that bad in that you lose efficiency points for every drop spilled or left behind somewhere. Essentially you need to figure out where you're weak points are in the process. Lautering? spilling? conversion? too much dead space in your MLT?

 

[Denny]

I am trying to track down efficiency issues. First all grain was 61%, next one was 65%. The latest one was 71%, and I've been keeping the temperature right at the mash temp. The 71% was mashed 10 mins longer, and I decocted it twice to keep it at 151 (it had dropped to 149 at 50 mins). Should I not worry about that temp drop? Since it was at the lower end of mash temps, I thought I should keep it up.

Meanwhile I've drilled holes in the manifold and evened out the slots, hoping to get some more points of efficiency. I guess I was putting a lot of emphasis on temp control, is that misplaced emphasis?

There was no need to worry about a 2 degree drop. When you did the decoctions, did you boil the grain? If you boiled the liquid, you likely denatured at least a portion of the enzymes.

Do you crush the grain yourself? The biggest cause of low efficiency is a poor crush. Do you fly sparge? Fly sparging shows the weaknesses of a lauter system. If you're fly sparging now, try batch sparging and see if your efficiency goes up.

 

[JayInAmes]

Thanks Denny, good to know about the 2 degree drop. I won't sweat that, I was just trying to keep everything even.

When I decocted I did boil mostly liquid, as I was trying not to introduce more water. I got myself into trouble the first all grain with not keeping track. This was on the last try, with the 10 minutes extra mash time. that was the best results I have gotten. I also batch sparge, but on this last try, I put foil with holes over the grain bed, and poured the sparge water as it drained out, kind of a fly sparge (got that method from an old thread from a mr Biermuncher). This was the best results.

i don't grind my own grain, and I suspect that is part of the problem. I left that alone for now, to see if I can clean up my technique. I'm not far off, and getting better at it. Eliminate one thing at a time. This time was modifying the manifold. I got a really slow sparge on the first wheat beer, probably didn't have that figured out quite right. We'll see this weekend, with Yooper's Fat Sam.

Everyone is a big help in this forum, and I thank you. I responded to this thread because of temp. I didn't mean to hijack it, but i guess I did, a bit. Not sweating about temps this time, and I'll just use a few towels.

 

[JayInAmes]

In regards to efficiency? Probably. It really depends on what efficiency you're talking about and making sure you know exactly what you're measuring. Brewhouse efficiency of 71% or a pre-boil efficiency of 71%? you need accurate gravity and volume measurement throughout your process to really track down where you losing juicy little sugars. If you're getting 71% brewhouse that's really not that bad in that you lose efficiency points for every drop spilled or left behind somewhere. Essentially you need to figure out where you're weak points are in the process. Lautering? spilling? conversion? too much dead space in your MLT?

Thanks for this. I've been keeping track of small things, and keep getting a little better. the 61-71% is pre-boil efficiency, from BeerSmith.

 

[Denny]

Thanks for this. I've been keeping track of small things, and keep getting a little better. the 61-71% is pre-boil efficiency, from BeerSmith.

Check what your conversion efficiency is. If it's not close to 100%, you have a problem to correct before you even get going.

 

[JayInAmes]

Check what your conversion efficiency is. If it's not close to 100%, you have a problem to correct before you even get going.

Measured mash efficiency in Brewsmith is 95% on the last batch.

 

[Denny]

Measured mash efficiency in Brewsmith is 95% on the last batch.

There seems to be a bit of confusion here...I thought you just said your mash/pre boil efficiency was 61-71%? If mash efficiency is truly 95%, then your conversion efficiency must be good. But if it's 61-71, then you need to look at conversion efficiency.

 

[JayInAmes]

There seems to be a bit of confusion here...I thought you just said your mash/pre boil efficiency was 61-71%? If mash efficiency is truly 95%, then your conversion efficiency must be good. But if it's 61-71, then you need to look at conversion efficiency.

I was reading from Brewsmith, and yes those should have been the same. Sorry about that. I have no idea where the 95% came from yesterday, as it doesn't say that today. I must have been messing with the numbers.

Today's brew, I had 11 lbs of Maris otter, 1 lb of Biscuit, and 1 lb of 60L Caramel. Pre boil gravity was 1.048. I used Brewer's Friend calculator, plugging in my grain bill, and got 64%. Brewsmith also gave me 61.3%. I mashed at 154 for 70 mins (dropped only 2 degrees) with 4 gallons of water. I batch sparged with 4.62 gallons of 168 water. These are the figures I got from Brewsmith. I should have have 6.92 gallons, but I only wound up with 6.5 gallons of preboil wort. I added 1/2 gallon of 1.020 wort I got from sparging the grain yet again with 1 gallon of hot water. Looks like I need to add to the mash tun deadspace by 1/2 gallon. It doesn't look like there is that much left when I scoop out the grain, but it is what it is.

OG was 1.057, with 5.5 gallons going into the fermenter after a 60 minute boil.