controlling Mash Temps

[BullGator]

I have a question about mash temps. I have been trying to hone in on my mask temps for awhile now. I just switched to all-grain but before that I was doing BIAB and I had the same problem. If a recipe calls for 154 deg, I would usually start out at around 149 and slowly ramp up to 154ish after around 30min. My question is, since there is only a certain amount of starch in the grain, am I missing my window by not hitting my temp right on from the beginning. I mean, the starch has to be converting to the more fermentable sugars while I am down at the lower temp before I can ramp up to 154. So once the starch is converted while at the lower temp, is it too late?

I am mainly looking at the amount of more-fermentable and less-fermentable sugars. If you compare 2 mashes: the first one hits 154 right on and mashes for 1 hour. The second one hits 149 for the first 30 min and then 154 for the last 30 minutes. Will both beers have the same body?

 

[hennesse]

The short answer - you're worrying too much. Relax - have a homebrew!

The traditional step-mash had 4 "rests" - temperatures where different enzymes did their best work. To understand our simplified "single-infusion" mash, we need to review what the last two stages of the step mash do.

John Palmer in How To Brew Chapter 14 describes it great detail - much better than I could ever do.

The rest at ~140 to ~150 allows β-Amylase (Palmer's hedge trimmer) to work on the ends of the starch molecules. The rest at ~158 to ~162 allows α-Amylase (Palmer's pair of clippers) to chop up the big starch pieces.

These are the temperatures where each amylase works BEST - but they also do their work at temperatures outside this range. So during the β-Amylase rest, the α-Amylase is working too, but not at full efficiency. The opposite is true too.

Consider that as you slowly increase the temperature towards mash-out, you're going through the range (158-162) where α-Amylase works best!

Our single-infusion mash temperature is a compromise where both α- and β-Amylase both work pretty well - the guy with the hedge trimmer and the guy with the clippers are making equal progress.

None of these wonderful chemical reactions happens instantaneously - that's why the mash takes 60-90 minutes to complete. You need to look at where your mash spends the majority of its time.

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With a RIMS or HERMS system, you dough-in at 152. The temperature immediately drops to about 142, and after 15 or 20 minutes, the sweet wort exiting your mash tun has finally reached 152. Isn't that just about the same as a step-mash β-Amylase rest?

You mash at 152 for 40 minutes (or perhaps 70) - both β and α are working simultaneously. They're starting at different ends of the starch tree and working their way towards the middle.

You turn the temp up to mashout (168 or 170), and it takes 15 or 20 minutes to reach that temperature. Isn't that just about the same as a step-mash α-Amylase rest?

Think about it - aren't we single-infusion folks are really doing a step mash? OK, it's a kinda "sloppy" step mash, but it is one just the same!

Many folks agree that a light body beer needs 148 degrees, while a medium is 152, and a full-body needs 156 --- for the 40-to-70 minute period where both β and α are working together. Don't worry about the ramp-ups at either end.

So, the long answer - you're worrying too much. Relax - have a homebrew!

Dave

 

[JuanMoore]

The wort profile will be slightly different between the beer that hits the mash temp right on and the one with the long ramp up period, but I'm not sure it's significant enough to worry about too much.

I know some people keep a little boiling water and room temp water handy to help quickly and easily adjust the mash temp if they're off. I've found that using Brewtarget or Beersmith and accurately inputting the mash tun info gives dough in temps that result in very accurate mash temps. I can't remember the last time I was off by more than two degrees.

---
With a RIMS or HERMS system, you dough-in at 152. The temperature immediately drops to about 142, and after 15 or 20 minutes, the sweet wort exiting your mash tun has finally reached 152.

I don't know many people who brew this way. Most people I know, including myself, try to use a dough in temperature that results in the mash settling at (or very close to) the target mash temp.

 

[RM-MN]

None of these wonderful chemical reactions happens instantaneously - that's why the mash takes 60-90 minutes to complete. You need to look at where your mash spends the majority of its time.

I'm going to differ with this statement and say that the majority of the mash time of 60 to 90 minutes isn't to let the enzymes work as they are quite quick. Most of that long mash is to get the grain particles wet through so the enzymes can do their work. An experiment I tried showed that with the grain milled really fine, conversion occured in less than 10 minutes but with a conventional mash tun you would never be able to get the wort out because the husks were torn up to much to make a filter bed.

Unless you have a great recirculation system, ramping up the mash temp is difficult because the heat doesn't circulate in a mash like it would if it was just water. You need to be stirring vigorously the whole time to avoid overshooting the temp in one spot while the thermometer in another will say you are too low. That's why most of us use a calculator for the strike water and stir the grain in to come to mash temp. We choose a compromise, cooler for a drier beer, hotter for a more malty beer.

 

[BullGator]

I am using a herms system and continuously recirc with a pump. However it takes time to ramp up the temp as it usually drops too low. Beersmith has been saying start at 168 but I guess I need to start higher? I will also start pre-heating my tun ( I am using an uninsulated keggle as a mash tun which may be part of my problem. ..).

As far as what palmer says. I need to go back and re-read that section now that I have actually brewed all-grain several times. But from the bits mentioned here maybe it doesn't matter as the 2 different alpha and beta which-a-call-its are eating different starch molecules anyways? It's just that they are more efficient in their respective ideal temp ranges? This would make sense to me. However this would be contrary to my original thought which is once the starch is converted you are done.

 

[billl]

If you aren't hitting your mash temps, then that is a problem and you should fix it.

No calculator is going to be 100% accurate. It's making all sorts of assumptions about your system and process that may or may not be true. If you use a calculator a couple times and it comes up 3-4 degrees short each time, then just add +4 degrees to the strike calculation next time. Just take good notes each brew day and you'll be able to dial in your temps pretty easily.

 

[broadbill]

If you aren't hitting your mash temps, then that is a problem and you should fix it.

No calculator is going to be 100% accurate. It's making all sorts of assumptions about your system and process that may or may not be true. If you use a calculator a couple times and it comes up 3-4 degrees short each time, then just add +4 degrees to the strike calculation next time. Just take good notes each brew day and you'll be able to dial in your temps pretty easily.

+1 to this...if you aren't hitting your mash temps, add/subtract degrees to do so on the next go-round.

Also, I've had mashes convert in 30 minutes, so I think hitting your mash temp on the first shot is pretty important to having a consistent brewing process. That is not to say you won't have good beer, I've made plenty of good batches where the mash temp/process was all messed up. What I'm saying is the goal of having a good process is an achievable and worthy goal.

 

[satph]

My understanding comes mostly from Palmer. The alpha turns starch into complex sugars. The beta turns starch and complex sugars into simple maltose.

Alpha works best [FONT=Verdana, Arial, Helvetica, sans-serif]154-162°F
Beta works best [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]131-150°F

Palmer notes that these are ranges and the enzymes work outside the range. But he also says the enzymes denature at temperatures above their range.

[/FONT]Here's another detailed explanation. The author suggests a low temperature rest and a high rest if you want a more complete conversion for an especially dry finished product. It seems to that you'd prefer to get the alpha working first creating complex sugars, then the beta to make simple sugars. But do you destroy the betas at [FONT=Verdana, Arial, Helvetica, sans-serif]155+°F, and how long does it take?
[/FONT]

 

[cluckk]

Beersmith has been saying start at 168 but I guess I need to start higher? I will also start pre-heating my tun ( I am using an uninsulated keggle as a mash tun which may be part of my problem. ..).

Have you entered the values for your particular mash tun into BeerSmith? For example your Mash Tun temperature and deadspace. Then in equipment profile there is a place for Mash Tun Specific Heat. It is preset for a plastic cooler (0.3) on some profiles. For a SS tun it should be changed to (0.13).

 

[billl]

"The alpha turns starch into complex sugars. The beta turns starch and complex sugars into simple maltose."

That isn't exactly true. Beta only works on the end of starch chains. It separates the last simple sugar and leaves the rest of the long chain intact. It keeps right on going right up the line one sugar at a time.

Alpha can work anywhere up and down the starch. It might break off that last sugar or it might break the starch in half or 1/3 vs 2/3 etc. Then it goes and breaks the remaining pieces at another random spot.

So, if you have a cutoff point of say 60 minutes, the beta would have almost all simple sugar and a few longer chains that hadn't been completely broken down yet. Alpha would have a bigger mix of simple sugars and medium length sugars. If you let the alpha keep going, it will continue to break down those medium sugars into simpler sugars.

As for denaturing, there is no bright line. In fact, they actually start to denature at temps even below their "optimal" ranges. The higher the temp gets, the faster they denature.

 

[BullGator]

Have you entered the values for your particular mash tun into BeerSmith? For example your Mash Tun temperature and deadspace. Then in equipment profile there is a place for Mash Tun Specific Heat. It is preset for a plastic cooler (0.3) on some profiles. For a SS tun it should be changed to (0.13).

I think I have beersmith set right. Although I'm still getting proficient with the program so I could have it screwed up (also beersmith isn't exactly an intuitive program in my opinion...but that's another thread topic). I will go in and verify. I have 2 questions though. Is there a limit on how hot your strike water should be? I want to keep it below 170 for some reason. Does everyone adjust the initial strike water temp based on the ambient temp? I would think you have to but I wanted to confirm.

 

[BullGator]

"The alpha turns starch into complex sugars. The beta turns starch and complex sugars into simple maltose."

That isn't exactly true. Beta only works on the end of starch chains. It separates the last simple sugar and leaves the rest of the long chain intact. It keeps right on going right up the line one sugar at a time.

Alpha can work anywhere up and down the starch. It might break off that last sugar or it might break the starch in half or 1/3 vs 2/3 etc. Then it goes and breaks the remaining pieces at another random spot.

So, if you have a cutoff point of say 60 minutes, the beta would have almost all simple sugar and a few longer chains that hadn't been completely broken down yet. Alpha would have a bigger mix of simple sugars and medium length sugars. If you let the alpha keep going, it will continue to break down those medium sugars into simpler sugars.

As for denaturing, there is no bright line. In fact, they actually start to denature at temps even below their "optimal" ranges. The higher the temp gets, the faster they denature.

This makes me think that my original thought process about this was correct. If I hit the initial temp right on the money and stop the mash at 1 hr (before it has a chance to further break down the medium chains as you indicated), then the beer should have more body compared to starting at a lower temp where those same starches are converted to simple sugars. Does this make sense?

 

[MuddyCreek]

I like the "ramp up" process because frankly, it's easier. However it is inherently difficult to duplicate precisely. That's the problem.

If I have a mash temp for a beer at say, 156 and I mash in and the temps start at 142 and start working up for say... 20 minutes, I can't absolutely guarantee the next time I make the same beer that my start temp will be exactly 142 and that it will take 20 minutes to ramp up. (Personally I brew on my back patio and weather does play a part in ramp-up times.)

While both brew-days may result in perfectly fine beer and those 2 beers may even be indistinguishable to my untrained palate, at the end of the day I have an essentially un-reproducible beer.

With just liquor and no mash, my HERM system requires the the HLT be 8 degrees higher than my target mash. Furthermore, I "preheat" the system by circulating my mash liquor through the HERMS system 10 degrees above my mash temp for about 20 or 30 minutes so my entire system is preheated and "set". That (so far) has netted a consistently close mash-in temp that is within a couple degrees of my target.

My process is by no means perfect, my HERM system still squirrels around sometimes trying to hit or maintain, but generally it works pretty well and is more reproducible than not...

 

[billl]

"If I hit the initial temp right on the money and stop the mash at 1 hr (before it has a chance to further break down the medium chains as you indicated), then the beer should have more body compared to starting at a lower temp where those same starches are converted to simple sugars. Does this make sense?"

You got it. It will also be a lot easier for you to replicate if you end up with a beer you love.