Raising Temp - Infusion Mashing

I was putting together a recipe for a high gravity brew and thinking of trying my first mash with multiple rest temps. However, with this high gravity brew, 2 rest temps and a mash out would leave me with almost no sparge water (.25 Gallon).

So my question is, what are the benefits/drawbacks/limitations to pulling the correct amount of liquid (and only liquid) from the mash and heating it to raise the temps?

Also, I use Beersmith so it gives the qty and temp of additions for the mash. Would there have to be any adjustments made to these numbers if I used the mash liquid instead of adding water?

Thanks for your input!

smithmd4 said:

I was putting together a recipe for a high gravity brew and thinking of trying my first mash with multiple rest temps. However, with this high gravity brew, 2 rest temps and a mash out would leave me with almost no sparge water (.25 Gallon). So my question is, what are the benefits/drawbacks/limitations to pulling the correct amount of liquid (and only liquid) from the mash and heating it to raise the temps? Also, I use Beersmith so it gives the qty and temp of additions for the mash. Would there have to be any adjustments made to these numbers if I used the mash liquid instead of adding water? Thanks for your input!

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if you are talking about grabbing a percentage of wort, boiling it down and adding it back you are talking about a decoction mash, not a step mash.

Decoctions can definitely change the flavor profile of a beer because you are boiling down and caramelizing a percentage of wort and adding it back. This creates a complex flavor profile but adds a lot of time to your brew day, perhaps turning a 4-5 hour session into an 8-9 hour day!

A step mash is simply performing a rest, adding in an additional amount of water to raise the temp and repeat. Some malts will benefit if under modified but most of today's well modified malts are fine with a single infusion mash.

I used to do step mashes with my Hefe but after doing a couple singles and not tasting a detectable difference I just do single infusion mashes for the most part.

Thanks duboman. I'm a single infusion brewer now, but want to play around with steps, mostly for alpha and beta activity.

Not a decoction per se. I'm not looking to pull liquid and grain, then boil for a specified period of time. Everything I find on Google is either decoction or step infusion with water and this isn't exactly either.

My thought is to just pull a specified portion of the mash liquid, heat it to the necessary temp, and add it back to the mash to raise the temp. Trying to work within the constraints of my own system and/or not thin the mash out a ton in the process.

By my rough guess, this would add 30-60min on to my brew session for 2 temp steps. I'm sure I would get some evaporation, and possibly some small color/flavor changes.

From my basic understanding of decoction mashing, the purpose of pulling mostly grain from the mash is to avoid denaturing the enzymes, since the enzymes are distributed into the liquid. If the liquid that contains the enzymes is heated instead of the grains, it could cause conversion issues.

How large of an issue, I don't know, but that is what I've read. Give it a shot though, maybe it won't be a big deal.

I've used the scenario that you outlined in order to raise my temps when I've missed my mash-in, or otherwise had a low-side temp miss. It doesn't work as well as I would like, but it still works. Generally I've pulled a gallon or two and brought it up to near boiling (190 or so), in the process discovering that I needed to do it slowly and with near-constant stirring to avoid scorching. Even then, it only raised the temp by about 5 degrees or so.

You can look at Palmer's (I think it's his) site and get the calculations for why (and how to predict the temp rise if you want). Basically, the temperature differential and masses are the two most important things - you're trying to raise several gallons of water and a dozen pounds of grain with only a couple gallons of water. That's not easy. And it's why I built a heat stick last weekend! Hopefully I don't melt my mash tun cooler.

smithmd4 said:

Thanks duboman. I'm a single infusion brewer now, but want to play around with steps, mostly for alpha and beta activity.

Not a decoction per se. I'm not looking to pull liquid and grain, then boil for a specified period of time. Everything I find on Google is either decoction or step infusion with water and this isn't exactly either.

My thought is to just pull a specified portion of the mash liquid, heat it to the necessary temp, and add it back to the mash to raise the temp. Trying to work within the constraints of my own system and/or not thin the mash out a ton in the process.

By my rough guess, this would add 30-60min on to my brew session for 2 temp steps. I'm sure I would get some evaporation, and possibly some small color/flavor changes.

Click to expand...

In reality you are doing more of a decoction then a step as you are using wort and not water to raise the temp. By heating a percentage of the wort you will change the flavor profile to some degree and you will find that the pulled wort will need to be heated to near boiling to get the next temp and if you don't pull enough you still need the heated water to get there.

You also need to pay careful attention to your volumes as your first runnings will be greater and require less sparge which may or may not drop your efficiency overall

With a decoction, mostly mash is pulled with only enough mash liquid to keep the mash from scorching. However, there is a conversion rest before bringing the mash to boil in the decoction kettle. Mash pH is important when boiling mash. If you pull mostly mash liquid before the mash is converted, the enzymes will be denatured and conversion will be reduced or halted. If you want to pull mash liquid and boil it, do it after conversion to reach mash out temperature.

VladOfTrub said:

With a decoction, mostly mash is pulled with only enough mash liquid to keep the mash from scorching. However, there is a conversion rest before bringing the mash to boil in the decoction kettle. Mash pH is important when boiling mash. If you pull mostly mash liquid before the mash is converted, the enzymes will be denatured and conversion will be reduced or halted. If you want to pull mash liquid and boil it, do it after conversion to reach mash out temperature.

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That's what I would suggest. You don't want to boil/heat the liquid of the mash until after conversion is complete, as the pH issue will be a problem as well as denaturing the enzymes needed for conversion.

Pulling liquid mostly is fine after conversion is complete, and is useful if that is needed to reach mash out temps.

I'd either skip step mashing, unless there is a specific reason to do it, or start with much less liquid (thick mash) and try it that way.

Thanks for all the replies and info!

I am also wondering what to do to solve this and have an idea.

You would need a pump and a copper manifold like whats in the bottom of cooler already but no holes and hook it up from HLT drain to pump to manifold and return to HLT. Like a hermes(exchanger in HLT) system but in reverse (exchanger in mash tun) so you don't have to pump wort, just water.
You could raise the grain bed temperature to whatever you want and the cooler will stay there. I was adding about two gallons of boiling water to mash to bring my 14Lb grain/mash up to mash out temp and resting about 15 min before sparge.
My cooler sometimes is over full trying to get to 170 for mash out on a couple batches now so I thought this would be an idea