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Converting a Step Mash Recipe into a Single Infusion Mash

I came across a clone recipe for a Spencer Trapist Ale. Recipe below:

10 lbs. (4.5 kg) North American 2-row Pilsner malt
2 lbs. (0.91 kg) North American 6-row pale malt
4 oz. (0.11 kg) caramel Munich malt (60 °L)
6.4 AAU Nugget hops (60 min.) (0.5 oz./14 g at 12.75% alpha acid)
1.2 AAU Willamette hops (10 min.) (0.25 oz./7 g at 4.75% alpha acid)
1 tsp. Irish moss (15 min.)
Wyeast 3787 (Trappist High Gravity) or White Labs WLP530 (Abbey Ale) yeast
Priming sugar (if bottling)

The recipe calls for a step infusion mash. I want to simplify this by doing it as a BIAB. Is there a calculator, formula or rationale used to convert to a Single Infusion Mash? Here is the mash schedule from the recipe:
Use a step-infusion mash starting at 148 °F (64 °C) for 75 minutes, then raise to 162 °F (72 °C) for 15 minutes. Raise grain bed to 168 °F (76 °C) to begin the lauter process. Sparge with enough water to collect about 6.5 gallons (25 L) of wort in the kettle. Boil for 90 minutes, adding the hops and Irish moss at the times indicated.

Thanks for any input. :slight_smile:

The intent of the 148F step is to active the beta-amylase enzyme to create very fermentable wort.

The intent of the 162F step is to deactivate the beta-amylase and enhance the alpha amylase activity in hopes of maintaining some dextrins and larger chain sugars with the goal of keeping the FG from bottoming out and maintaining some level of sweetness and body.

The intent of the 168F step is to gelatinize all starches to make run-off easier and to deactivate the alpha-amylase enzyme to stop the conversion process. (i.e. Mashout)

You could safely do a single infusion mash at between 148F and 153F for X minutes without any significant impact on the end result. It won’t be the same, you’ll end up with a slighter drier beer or perhaps a slightly more dextrinous beer but it will be close enough for government work.

The key would be to raise the temperature of the wort to mashout at the point where you think there’s a balance between dextrins and fermentability (is that a word?). That point may be 60 min.,75 min., or 90 min. or any point in between.

Here is some excellent information:

Thanks to you both. This is great information. In every discussion of BIAB, I have never heard of step mashing being used. I assume that repeated application of heat can increase the chance that the bag and/or grains on the bottom may scorch. Is this a short-fall of the BIAB technique?

Most of the time the bag is held off the bottom by a basket or an inverted pizza pan with holes drilled in it or even just a false bottom used under a grain bed.

In my extended testing of mash schedules, I really haven’t found any reason to do a step mash. I still do one a couple times a year to make sure I haven’t overlooked anything and so far I haven’t found anything to change my mind. I’d do your recipe as a single infusion about 152F. A couple degrees one way or the other won’t matter.

Mash schedules are created with good intentions, though. Perhaps more meaningful at a professional level.

Most of the time the bag is held off the bottom by a basket or an inverted pizza pan with holes drilled in it or even just a false bottom used under a grain bed.[/quote]

This is true. And I suppose that constant stirring with the mash paddle until the desires mash temp is reached will also help. As Denny and you suggested, there is probably no reason to step mash nor any real difference in the finished beer. I want to keep it simple.

Denny, how did you arrive at 152F? Is there a rule of thumb to go by, or is it through experience, or is it an educated guess based on the step mash schedule?

Mash schedules are created with good intentions, though. Perhaps more meaningful at a professional level.[/quote]

Very few commercial brewers use a step mash compared to those who use single infusion. The malt doesn’t need steps these days and the extra energy to do step (or decoction) mashes costs too much. Maltsters are producing malts intended for single infusion to save the breweries money.

It’s an educated guess based on the temps you gave, buffered by the fact that a few degrees won’t matter.

It’s an educated guess based on the temps you gave, buffered by the fact that a few degrees won’t matter.[/quote]

Thanks again. That’s what I thought, just wanted to make sure. This is all great information.

Mash schedules are created with good intentions, though. Perhaps more meaningful at a professional level.[/quote]

Very few commercial brewers use a step mash compared to those who use single infusion. The malt doesn’t need steps these days and the extra energy to do step (or decoction) mashes costs too much. Maltsters are producing malts intended for single infusion to save the breweries money.[/quote]

True, provided they are not using undermodified malt or have nay in their recipe. Not sure where the OP got the recipe from.

True, provided they are not using undermodified malt or have nay in their recipe. Not sure where the OP got the recipe from.[/quote]

I found it here: https://byo.com/stories/issue/item/3114 … -ale-clone

Thanks again for all the input.

I made this exact recipe in the spring and asked some of the same questions. Somewhere there is a thread. I had decided to do a single infusion and mash at 151 degrees. I was a bit under and mashed at 148. This beer came out really nice. It was dry, crisp and picked up some fruitiness from the yeast. Not too much fruitiness but just enough. It was a really nice beer that got better as it aged. The last few pints in the keg were great!

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