Originally Posted by Burgs
Can this method be used for all-grain recipes that call for more complex mash schedules? Do you just leave the pot covered and turn up the heat when you need to step between the mash temperatures?
I've been experimenting with more "complicated" mash techniques for BIAB(None were really difficult, just different ways to do it).
The sum of my experience for myself is to just apply direct heat, slowly to the kettle (Using an electric stove with the coils). I got a grain bag from a brewing website, so I can't say anything for the paint strainer bags (which are often disposable), but the direct heat doesn't damage my bag. While doing this, I usually try to get my bag suspended, and not sitting on the bottom at the direct heat. I do this for the grain more so than the bag. And the key to this is: stir, stir, stir. Stiring moves around the grain and brings the temperature of the mash tun to an equilibrium. Don't leave it sitting for too long, you will scorch the grains on the bottom, which is much hotter than the top. You will lose heat from stirring, but keeping the grains moving is more important. Doing this, I've had my burner on almost full power. This can allow you to get to different steps, but it isn't the only way.
Infusion is possible, but with my setup, I don't have a lot of room to add the water required to step things up. As DeathBrewer states, after you mash in, you want to be as close to the top of the kettle as possible to reduce headspace and slow the cooling of the mash tun. Doing this works well, but will leave you with NO room to infuse.
A better option is decoction. I don't see why you can't do this like a normal mash tun requires, but will likely have its difficulties. The amount of time it takes for decoction is something you have to not only consider for your brewday, but for your mash tun and the rest as well. When taking off a portion of your mash to boil, the part that is left is going to cool faster, and for the time it takes to rest and boil the decoction, will loose temperature. You might be able to compensate for this by pulling a bigger decoction to make up for the loss, but knowing exactally how much will take practice.
All of these things I've tried take practice to get right for MY system. If you have more room in your kettle, maybe infusion is a more legit option. If you use gas to heat the mash tun, maybe direct heat isn't best for you. Try things out, you'll no doubt not get it right on your first try, but you'll learn a lot about your process, and it's benefits and faults
I did this recently to brew an Agave Wheat beer. I gave it a ferulic acid rest at 114F (for the 4vg) for 15 minutes, then brought it up to 152F for the main rest. Worked out fine, and I got 73% efficiency. It was also much easier to keep a temp for the main rest with the heat on low, rather than wrapped in towels. I only fluctuated a couple degrees, then could quickly correct for it.
If anyone else has any experience, I would love to hear it. I don't think I'll be moving on to a traditional mash tun anytime soon until I see more limitations with this method.