Water displacement from grain?

[FatDragon]

In my search for a sweet stout recipe to brew for my second brew and first BIAB, I decided to download BeerSmith and give it a try with the 21 day free trial.

I spent a bit of time spitballing a recipe and customized an equipment profile for my 35x35cm kettle (just a hair shy of 9 gallons), for which I have a cut-to-fit BIAB bag. For a grain bill of about 12 pounds, BeerSmith recommended I mash in something like 7.25 gallons of water (it's on my laptop, can't access right now for exact numbers). It seems to me that adding 12 lb. of grain would cause an overflow there.

If I'm trying to do 5 gal. batches, what size grain bill can I do without splitting and doing two mashes? My next brew will probably be on a workday (after 5 PM) so taking the time for a second mash means finishing quite late. A bigger pot, while affordable here in China, would be too big for my stove, and I wonder if larger mashes that way wouldn't require too much water, which would then require a long boil-off to get down to my 5.5 gallon fermentation batch size.

Finally, if anybody wants to share a killer AG recipe for a sweet stout that doesn't require too many specialty grains (anything but two-row costs about $7.50/lb.), that would be excellent.

 

[Yooper]

Check out the "can I mash it" calculator tool on rackers.org. I use it all the time to calculate how much space a grainbill will take up on any given batch.

It's here: http://www.rackers.org/calcs.shtml about 1/2 way down the page.

 

[FatDragon]

Check out the "can I mash it" calculator tool on rackers.org. I use it all the time to calculate how much space a grainbill will take up on any given batch.

It's here: http://www.rackers.org/calcs.shtml about 1/2 way down the page.

This is a good start, but I'm a bit confused about how to use it. The weight of the grain bill makes enough sense, but the mash thickness is a bit more mysterious to me. I understand 1.25 qt/lb is the standard for a mash/lauter tun, but how does sparging/no-sparge/mashout/BIAB affect this? I'm mostly confused because BeerSmith wanted me to use ~9 gallons of water to no-sparge BIAB mash ~12 lb in a 13 gallon kettle (before I found I could customize my own equipment in the software), and over 7 gallons in a 9 gallon kettle, both of which are way higher than the 4.71 gallons I get from this calculator.

 

[Yooper]

This is a good start, but I'm a bit confused about how to use it. The weight of the grain bill makes enough sense, but the mash thickness is a bit more mysterious to me. I understand 1.25 qt/lb is the standard for a mash/lauter tun, but how does sparging/no-sparge/mashout/BIAB affect this? I'm mostly confused because BeerSmith wanted me to use ~9 gallons of water to no-sparge BIAB mash ~12 lb in a 13 gallon kettle (before I found I could customize my own equipment in the software), and over 7 gallons in a 9 gallon kettle, both of which are way higher than the 4.71 gallons I get from this calculator.

I don't understand the question.

If you're asking how much water you can add to the grain to mash in a BIAB system, the answer is "until it's full". I don't know if that will be 1.5 quarts/pound, 2.5 quarts/pound or something else, but if it's full (no matter what Beersmith says), no more is going in there!

 

[FatDragon]

I don't understand the question.

If you're asking how much water you can add to the grain to mash in a BIAB system, the answer is "until it's full". I don't know if that will be 1.5 quarts/pound, 2.5 quarts/pound or something else, but if it's full (no matter what Beersmith says), no more is going in there!

I guess my question is how much water should I add per pound of grain for a BIAB brew? I've seen various discussions about how much grain you can mash in a certain kettle size with BIAB, and I imagine that comes down to the "mash thickness" (as defined by that calculator - I'd never heard the term before). Effectively what does a higher water-to-grain ratio give a brewer, and why should I go higher than 1.25 qt/lb for BIAB with a mashout? My thinking is if I keep a standard 1.25 qt/lb mash thickness I can do big beers with a single mash, and either increase the thickness or top off for volume if I do a smaller beer. However, there's a whole lot I don't know, so I could easily be wrong here.

Sorry for all the questions, my intention is to learn rather than to be annoying, but I might be doing a bit of both for now.

 

[Yooper]

I guess my question is how much water should I add per pound of grain for a BIAB brew? I've seen various discussions about how much grain you can mash in a certain kettle size with BIAB, and I imagine that comes down to the "mash thickness" (as defined by that calculator - I'd never heard the term before). Effectively what does a higher water-to-grain ratio give a brewer, and why should I go higher than 1.25 qt/lb for BIAB with a mashout? My thinking is if I keep a standard 1.25 qt/lb mash thickness I can do big beers with a single mash, and either increase the thickness or top off for volume if I do a smaller beer. However, there's a whole lot I don't know, so I could easily be wrong here.

Sorry for all the questions, my intention is to learn rather than to be annoying, but I might be doing a bit of both for now.

Haha- you're not annoying at all. I just really didn't understand what you're asking.

The advantages for traditional AG brewers for mashing thicker vs thinner is that we'll have more sparge water in the end, as well as have a less fermentable wort. Mash pH plays a part as well.

I don't do BIAB, so those questions you have are good questions, and I'll have to defer to the BIAB folks. Some sparge, some don't- so that might make it even more confusing, but they'll do their best to help, I"m sure!

 

[FatDragon]

Haha- you're not annoying at all. I just really didn't understand what you're asking.

The advantages for traditional AG brewers for mashing thicker vs thinner is that we'll have more sparge water in the end, as well as have a less fermentable wort. Mash pH plays a part as well.

I don't do BIAB, so those questions you have are good questions, and I'll have to defer to the BIAB folks. Some sparge, some don't- so that might make it even more confusing, but they'll do their best to help, I"m sure!

WRT the bold - looks like All-Grain brewing is going to be like learning Chinese: the more I know, the more I know I don't know. So thinner=more water per lb=more fermentable sugars? What's the benefit of having more sparge water and a thicker mash versus less sparge water (or no sparge water) and a thinner mash?

And in the hopes that one of the BIAB folks will chime in (otherwise I'll have to go through the dreaded step of searching for information myself), what water:grain ratio should I be using for 5 gallon BIAB in a 9 gallon pot?

 

[ajf]

1 lb grain when mixed with water to thoroughly wet it occupies a volume of 0.32 quarts, so if you start with 12 lbs of grain, and add 7.25 gallons (29 qts) water, the total volume will be 29 + 12 * 0.32 qts = 8.21 gallons. That should fit in you ~9 gallon pot just fine. However, Starting with 7.25 gallons of water, and assuming a grain absorbtion of 0.12 gallons per pound, will leave you with 7.25 - 12 * 0.12 = 5.81 gallons of wort. If this is insufficient wort for you (pre-boil) you could either reduce your batch size, or do a sparge with the extra water that you need.
Of course, if you squeeze your sack, then your grain absorption will probable lb less than 0.12 gallons / lb, but I never do that as I never BIAB.

-a.

 

[beernut70]

Check out the spreadsheets on the link below. I use the google docs version and as you get your system dialed in you can adjust the absorption. I squeeze the bag a lot and have the absorption set to .05 gallons per pound. Should probably use the default and adjust from there. As far as mash thickness use the full volume if you can fit it in your pot.


http://www.homebrewfinds.com/2012/03/start-all-grain-brewing-for-4-water.html

 

[FatDragon]

Thanks to all for the help. I think I understand more of the concepts involved now and can better wrap my head around what I'm doing here.

In a nutshell, here's how I understand it now:

BIAB mash water volumes are targeted to ensure that the recipe ends up at the proper batch volume after absorption and boil-off. For that reason, to an extent, water volume between different-sized grain bills only differs by the absorption rate - so if ten pounds absorb a gallon of water, adding ten pounds of grain requires an extra gallon of water. The pre-boil volume is the amount of water you should have after mashing but before removing the grain bag, but the actual volume of materials in the kettle will be .32qt greater per pound, so a 12lb grain bill with a pre-boil volume of 8 gallons will actually come just shy of filling a 9 gallon kettle. Correct?

I knew BIAB was a form of All Grain, as well, but I used BIAB and All Grain to differentiate between single vessel BIAB brewing and three-vessel traditional AG brewing.

 

[beernut70]

Your right on the money now. I used a 9 gallon pot for quite a while, now I have a keggle. I like to keep things simple so when I wanted to do a bigger beer I would just change the batch size to what I could fit in my pot. Never bothered me to make 4 gallons instead of 5.

If you do want to make a bigger beer than would fit in your pot you could also just dunk sparge into the remaining water to hit your volume. The grain has already absorbed as much water as it can so if your 2 gallons short just dunk the bag in 2 gallons of water.

 

[ajf]

Very nearly right.
The pre-boil volume is the amount of wort in the kettle, after removing the grain bag. This will be (as near as makes no difference) equal to the amount of water added less the amount of water absorbed by the grain.
As beernut said, your system is unique, and your grain absorption, and boil off rate will probably be slightly different to the defaults used in calculators. Take careful measurements as you brew, and make notes.
You can always tweak the process for the next brew. It took me about 3 or 4 brews to get my volumes set up correctly, but each of those early brews was very drinkable.

Good luck,

-a.

 

[reverendj1]

I dunk sparge with BIAB (i.e. dunk the bag in water to rinse it). I always use 4 gallons of water for my mash and two for my sparge for a 5 gallon recipe, regardless of grain bill. That generally gives me ~5 gallons for the boil, and I get ~.5 gals of boil-off in an hour, so I always overshoot my OG, and I can just top up with water to bring it down to where it's supposed to be. Seems to work for me.

 

[beernut70]

Oops! Didn't pickup the before removing the grains. What AJF said...

 

[1MadScientist]

I spent a bit of time spitballing a recipe and customized an equipment profile for my 35x35cm kettle (just a hair shy of 9 gallons), for which I have a cut-to-fit BIAB bag. For a grain bill of about 12 pounds, BeerSmith recommended I mash in something like 7.25 gallons of water (it's on my laptop, can't access right now for exact numbers). It seems to me that adding 12 lb. of grain would cause an overflow there.

If I'm trying to do 5 gal. batches, what size grain bill can I do without splitting and doing two mashes? My next brew will probably be on a workday (after 5 PM) so taking the time for a second mash means finishing quite late. A bigger pot, while affordable here in China, would be too big for my stove, and I wonder if larger mashes that way wouldn't require too much water, which would then require a long boil-off to get down to my 5.5 gallon fermentation batch size.

That's what I would do. 7.25 gallons of strike water with 12 lb. of grain, this will get you at 1 inch from the brim. You then can either sparge with the remaining 1.59 gallons or add it in as a pre-boil dilution. This will produce 5.5 gallon in the fermenter.

 

[FatDragon]

Very nearly right.
The pre-boil volume is the amount of wort in the kettle, after removing the grain bag. This will be (as near as makes no difference) equal to the amount of water added less the amount of water absorbed by the grain.
As beernut said, your system is unique, and your grain absorption, and boil off rate will probably be slightly different to the defaults used in calculators. Take careful measurements as you brew, and make notes.
You can always tweak the process for the next brew. It took me about 3 or 4 brews to get my volumes set up correctly, but each of those early brews was very drinkable.

Good luck,

-a.

Hmm, I see. The BIAB volume calculator that someone linked several posts ago gives numbers like this:

Pre-Boil Volume needed: 4.52 gallons
Absorption Loss: 0.77 gallons
Boil Loss: 0.50 gallons
Final Batch Size: 3.25 gallons

So I was getting my "pre-boil volume equals the volume of liquid (not counting volume of the grain solids) before the grain bag is removed" definition from that, where they're clearly calculating the water that is absorbed in the grain as part of the pre-boil volume. I guess as long as the numbers are right, the terminology is secondary.

What would the term be for "volume of liquid after mashing but before removing the grain bag" (what I was calling "pre-boil volume"), or does it even really matter?

 

[Carlscan26]

I've always thought that pre boil volume was just that - your volume immediately before you boiled. So yes after the grains are removed.

 

[BadDeacon]

I do BIAB as well. I mash w 1.5 - 2 gal per pound of grain and the lift and tie off my basket and let it drip into the pot. This allows me to sparge w water through the grain to get to my preboil volume. Also, I mash out at 170 for 10 min prior to lifting the basket.

I know this is not as accurate as other formula but it fits my equipment. And has given good results. Efficiency is usually 75-85%.

 

[Powerturn11]

I dunk sparge with BIAB (i.e. dunk the bag in water to rinse it). I always use 4 gallons of water for my mash and two for my sparge for a 5 gallon recipe, regardless of grain bill. That generally gives me ~5 gallons for the boil, and I get ~.5 gals of boil-off in an hour, so I always overshoot my OG, and I can just top up with water to bring it down to where it's supposed to be. Seems to work for me.

Almost exactly what I do. For simplicity I always use 6 gallons of water for my mash and then I bring up to desired pre boil volume with 170 degree sparge water. Always get 75 to 80% eff. Easy and effective.

 

[beernut70]

The spreadsheets should probably read "Volume Needed" not preboil volume. Your preboil is simply the boil-off + batch size.

 

[ajf]

Hmm, I see. The BIAB volume calculator that someone linked several posts ago gives numbers like this:

Pre-Boil Volume needed: 4.52 gallons
Absorption Loss: 0.77 gallons
Boil Loss: 0.50 gallons
Final Batch Size: 3.25 gallons

So I was getting my "pre-boil volume equals the volume of liquid (not counting volume of the grain solids) before the grain bag is removed" definition from that, where they're clearly calculating the water that is absorbed in the grain as part of the pre-boil volume. I guess as long as the numbers are right, the terminology is secondary.

What would the term be for "volume of liquid after mashing but before removing the grain bag" (what I was calling "pre-boil volume"), or does it even really matter?

The "volume of liquid after mashing but before removing the grain bag" is normally referred to as the "space required". The only time it matters is if you take a gravity reading prior to the boil, to calculate the amount of extra fermentables to add during the boil to achieve the desired gravity.

-a.

 

[Carlscan26]

The "volume of liquid after mashing but before removing the grain bag" is normally referred to as the "space required". The only time it matters is if you take a gravity reading prior to the boil, to calculate the amount of extra fermentables to add during the boil to achieve the desired gravity. -a.

Wouldn't you want the volume without the grains since you wouldn't be boiling with the grains in the pot?

 

[ajf]

Yes you would.
Perhaps I should have said that for such a calculation, you need the true pre-boil volume, and not the space (or volume) required.

-a.