Still confused on mashing / sparging, crazy idea maybe...

[Shaika-Dzari]

Hello everyone,

New brewer here using BIAB and doing 1 gallon batch.

My first recipe was from a book by Brooklyn BrewShop.
The recipe asked to mash the grain with 2.37L of water at 65C (151F) then sparge with 3.79L of water at 77C (170F) after 60 minutes.

I don't understand why 2.37L / mash and 3.79L / sparge... Is it really making a different of much liquid I use to mash the grain ? I mean, in theory, there is a maximum quantity of sugar I'm trying to extract and I don't understand why the quantity of liquid impact that. My understanding was that temperature is what is more important.

Also, maintaining correct mashing temperature during 60 mins with small volume is a bit more challenging. I currently put my kettle in my oven after pre-eating it to 170F and letting cool a bit. One crazy idea I had was to heat water to 160F on the side and then, every 15 mins, add something like 250ml of this water to the mash to raise / maintain the temperature. Is it a crazy idea ?

FYI: my current efficiency is 65-67 % ...

 

[schmurf]

If you're doing BIAB you might just as well do full volume from start, I suspect the difference in efficiency, mouth feel and what not is not worth the bother.

 

[doug293cz]

If you are doing a traditional fly sparge, then saving as much water for sparging is the way to maximize lauter efficiency (which is one of the two components of mash efficiency.) If batch sparging (or it’s BIAB equivalent: dunk sparging) then you want all of you run-offs to have roughly the same volume. For a single batch sparge, using about 60% of your total brewing water for the mash (strike volume) and 40% for sparge will get you as close as you need to be for equal run-offs. The extra water for strike is required to account for grain absorption.

Using more, rather than less, water in the mash is a good thing, as thinner mashes convert a little faster than thicker mashes.

As far as sparge or no-sparge goes, a single batch sparge will give you 8-9% higher lauter efficiency than no-sparge (all else being equal). Lower efficiency is easily made up by adding some extra grain to the mash. You should make your decision to sparge or not depending on what works best for you. Highest efficiency isn’t really important at the homebrew level.

If you want to hold water out of the mash, to add later to make up heat loss, then you should use boiling water to get the biggest temp rise for the least amount of added water. There are lots of step infusion calculators that you can use to calculate how much boiling water you need to add to a particular mash volume to get a specific temp rise.

Brew on

 

[Shaika-Dzari]

Hey thanks both of you!

My current method is to put the grain bag in a strainer over my wort and put water over the bag. The first liter of water I put over the bag, you can clearly see good stuff coming off (ie, same color as the wort) but after 2L it start being fairly light and "watery". I don't really care about efficiency to be honest, I mostly try to understand the "why" and be consistent.

I think I will experiment a bit next time. Use a thinner mash, mostly invert the instruction of my recipe (mash with 3.79L, sparge with 2.37L) and check my gravity.

I'll also check for a step infusion calculators. New stuff to read and learn I guess

 

[Leezer]

I do biab 1 gal and 2 gal batches and have found it easiest to do full volume. Like you I put the grain bag in a strainer over the wort after the mash but then I just press down on it several times with a glass Pyrex measuring cup to squeeze some more out if it. To maintain mash temp I used to use a warm oven but find that by wrapping the kettle on the stovetop (heat off) with a blanket and a couple beach towels I only lose 2-3 degrees over the course of an hour. I used to check the temp during the mash but found it's better to just leave it covered up since only losing a few degrees seems to work out fine. After awhile you'll find a process that works for you.

 

[Bobby_M]

It's easy to oversparge with a pour over. If you must sparge, I'd dunk the bag.