Anyone have expereince doing a step mash with BIAB?

[msa8967]

I have been thinking of trying a step mash beer and would like to know if anyone has experience doing step mash beers with BIAB. If so, is there any thing I should modify in a given recipe that uses a traditional mash tun for doing BIAB?

 

[RM-MN]

What will you be trying to accomplish with a step mash? What rests will you be trying to hit? How will you heat to reach each step? Will you mill your grains very fine for BIAB?

The last 2 questions relate to how fermentable you want your beer. To make the beer less fermentable you need to mash fairly high. Doing a step mash, you will be heating your wort through the temperature where the beta amylase is more active and it may have made the more fermentable sugars before the alpha amylase even begins to become active.

 

[Riot]

If you don't want to apply heat to reach steps both decoctions and infusions work with BIAB. I am also wondering what you're trying for with the multiple temp rests, most beers really don't need more than a single infusion.

 

[NTexBrewer]

I'm tagging along because I too am about to do a beer that recommends a protein rest at 122 before stepping up to 151 for the mash.

In my case I'm using grains that I malted myself. Since I did the malting, my grains are not as efficient as store bought grains so the protein rest is recommended.

I was planning to do a decoction. Does anyone know of a good calculator?

 

[Scutrbrau]

I just brewed a Flanders Pale that had the following steps:

- Dough-in to hit 122º and hold for 20 min.
- Raise to 145º and hold for 40 min.
- Raise to 162º and hold for 30 min.
- Raise to 169º and hold for 10 min.

I tried raising the temp doing infusions based on calculations from Brewers Friend but didn't even come close to bringing it up high enough. The simple version of the recipe called for mashing at 150º and I had no problem getting it there and holding it, but 153º was the best I could do. I'll try this again but I'll do it by applying heat instead of doing infusions.

 

[Riot]

The best advice I've ever seen for doing decoctions is to pull more than you will need and add it in parts until you hit your rest temp. It's way too easy to undershoot volume and not be able to get it high enough.

 

[Foosier]

I have not done a true "Step mash" but I do mash out with direct heat while the bag is in place. I just make sure to keep stirring the mash while the heat is on. Works pretty well. I would think you could do the same to hit your mash steps. It would just be dough in to first step, heat and stir to second step, heat and stir to third step, etc... Only issue there is it would not necessarily be fast.

 

[dustinstriplin]

What will you be trying to accomplish with a step mash? What rests will you be trying to hit? How will you heat to reach each step? Will you mill your grains very fine for BIAB?

The last 2 questions relate to how fermentable you want your beer. To make the beer less fermentable you need to mash fairly high. Doing a step mash, you will be heating your wort through the temperature where the beta amylase is more active and it may have made the more fermentable sugars before the alpha amylase even begins to become active.

Would it be fine to pull the bag out while the wort is being heated up to the next step? Thereby skipping the beta amylase temperatures, and going straight to the alpha amylase temps.

 

[Foosier]

You could but I am not sure what you would gain by doing that.

While the bag is in the wort you keep extracting sugars and converting starches. If you pull the bag you will at a minimum stop extracting sugars. You will also lose heat from the grain. I would just not see the benefit in doing this. Violates the KISS method which I think is a key component of why we go BIAB.

I would keep it all together and stir while heating.

 

[dustinstriplin]

You could but I am not sure what you would gain by doing that.

While the bag is in the wort you keep extracting sugars and converting starches. If you pull the bag you will at a minimum stop extracting sugars. You will also lose heat from the grain. I would just not see the benefit in doing this. Violates the KISS method which I think is a key component of why we go BIAB.

I would keep it all together and stir while heating.

I was thinking that you could quickly raise the wort temp without worrying about scorching the bag. You also wouldn't need to stir so much because you don't need to even the temp out throughout the grain. I've never done a step mash, and I don't know much about the process other than what I've gleaned from the things I've read.
Two issues are cooling the grain, and missing the intermediate temperatures between rests. If the cooling of the grain is an issue then removing the bag would be a bad idea. Also, if you want a steady progression through the different temperatures then there is an issue with removing the bag.
If both the progression through the intermediate temperatures, and the grain cooling aren't issues, then it seems to me that removing the bag is in fact easier, because you don't need to worry about scorching the bag, or stirring the grains to distribute heat.

 

[Foosier]

I would agree with you that if progression and cooling are not issues that removing the bag would eliminate the need for stirring. I doubt you would find it to be truly easier though. Pulling the bag is messy enough at the end of the mash. Doing it multiple times would be worse. I would think it would also be a challenge getting the bag back in without making a mess. Granted, this is based on conjecture, not experience.

If I wanted to limit stirring while raising the mash temp, I think I would look at trying to suspend the bag in the wort so it was not on the bottom. This could either be by a pully system holding the bag up or an insert in the bottom of the kettle to keep your bag off the bottom. Either would work. However, by not stirring you are not going to be distributing heat through the mash efficiently. Also, stirring helps to dissolve sugars from the grain. As a result, not stirring could, probably not significantly, lower your efficiency.

I'd be interested to hear how it goes if you try it.

 

[BlueHouseBrewhaus]

I have done a few infusion step mashes with my BIAB setup (wheats and Belgians). Infusion brings you to your next step faster than direct heat and you don't have to worry about scorching the bag. Doing infusions depends on the size of your pot. You also need a second pot to heat your infusion water. My main pot is 9 gal with a turkey basket for the grain bag and I use my old 5 gal pot for infusion water.

For a 5 gal batch, I start with the entire volume in my main pot (usually 7.5 gal) and add any water adjustments. Then I transfer all the water except my initial mash water to the 5 gal pot. I heat the mash water in the main pot to the strike temp for my first step. Turn off heat, put basket and grain bag in, and dough in grains. To reach the next step, I typically heat the infusion water to boiling and figure out the correct amount to bring the mash to the next step. I have done three-step mashes with this process with good results.

I use BeerSmith 2.0 Mobile to calculate strike and infusion temps. I use the calculator in the Tools section. For some reason this gives me more accurate strike temps than the mash profiles give in an actual recipe. It also allows me to play around to figure out how much boiling water each step will take. I almost always hit my temps within a degree using this.

A couple of caveats. Yes, this is not quite KISS but I can still do the whole thing on my stove top. With bigger beers (>1.060) I usually can't fit all the water in the main pot. I still can fit enough to do my steps but then I lift the bag and sparge with whatever is left over. It's all much easier than it sounds once you have the system down.