BIAB OG question

[jrodder]

So I am trying to wrap my head around this issue. If I want to brew something like Centennial Blonde in a 23Q vessel with BIAB, calculators/calculations are showing I need 8 gallons of water to end up with 5.5 in my fermentor, to end up with 5 gallons of beer.

Why can't I just mash into the 5 gallons or even 1.25q/lb, and then add water to get it to 5 gallons of wort to boil? (very little boils off on the stove)

I mean, the amount of sugars is the same, no?

 

[LLBeanJ]

Why can't I just mash into the 5 gallons or even 1.25q/lb, and then add water to get it to 5 gallons of wort to boil? (very little boils off on the stove)

You can. If you just add straight water to the boil you'll likely wind up with lower efficiency due to not doing the full-volume mash. However, if you can do some sort of sparge, say by dunking the grains in the water you want to add in, or pouring the water over the grains before adding it to the BK, you'll likely improve your efficiency beyond what you would have gotten had you done a full-volume mash.

 

[tre9er]

You can. If you just add straight water to the boil you'll likely wind up with lower efficiency due to not doing the full-volume mash. However, if you can do some sort of sparge, say by dunking the grains in the water you want to add in, or pouring the water over the grains before adding it to the BK, you'll likely improve your efficiency beyond what you would have gotten had you done a full-volume mash.

This. Because you get more sugar with a "rinse" of the grain rather than just topping off with water, your efficiency will be low. If you don't care, adjust the recipe to use more grain and cheers.

 

[jrodder]

Is there a way to calculate exactly how much more grain I would need to add to the Centennial Blonde recipe then, if I am planning on using the 23L kettle and some type of dunk sparge? Let me rephrase, I am sure there *is* but maybe I am just not seeing how to do it.

 

[tre9er]

Is there a way to calculate exactly how much more grain I would need to add to the Centennial Blonde recipe then, if I am planning on using the 23L kettle and some type of dunk sparge? Let me rephrase, I am sure there *is* but maybe I am just not seeing how to do it.

Recipes are based on efficiency, which is how much sugar you get from the grain versus the total potential sugar the grain holds. Doing no sparge or a dunk sparge probably puts you in the 65% efficiency range, just a shot-in-the-dark here.

You'd need to check the efficiency of the recipe, then adjust for yours. I would hope you're using software of some sort to customize recipes to your specific system.

 

[LLBeanJ]

Piggybacking on what Tre9er said, until you've brewed a few batches and can figure out where the efficiency for your all grain system really falls, any attempt to compensate for lower/higher efficiency would be a shot in the dark. If I were you, I'd go with the base recipe of Centennial Blonde, which I believe is based on 70% efficiency, and just see how it comes out. Doing any kind of sparge will get you better efficiency than not doing one, so do it if you can, but if you can't, don't worry about it. The result will be beer. Also, if you don't have any brewing software already, download the free trial of Beersmith or one of the other free titles that are out there and start playing around with it.

 

[Ridire]

I only have one BIAB under my belt but here is what I did (any more experienced guys please tell me if there is a problem with this - beer turned out great):

1. mashed in my boil kettle with 1.5 qts of water per 1 lb. of grain (roughly 5 gallons for my grain bill).

2. In a separate pot, I heated 3-4 gallons of water to around 170 degrees.

3. After the 60 minute mash, I removed my bag from the boil kettle, placed it in a 7 gallon Ale Pail and rinsed it with some of my 170 degree water (squeezing the bag).

4. I added the water from step 3 to my boil kettle and repeated until I had 6 gallons of pre-boil volume in my boil kettle.

5. 60 minute boil brought volume down to nearly 5 gallons.

EDIT: this way, I could do a full-boil 5 gallon batch with my 7.5 gallon turkey fryer.

 

[tre9er]

I only have one BIAB under my belt but here is what I did (any more experienced guys please tell me if there is a problem with this - beer turned out great):

1. mashed in my boil kettle with 1.5 qts of water per 1 lb. of grain (roughly 5 gallons for my grain bill).

2. In a separate pot, I heated 3-4 gallons of water to around 170 degrees.

3. After the 60 minute mash, I removed my bag from the boil kettle, placed it in a 7 gallon Ale Pail and rinsed it with some of my 170 degree water (squeezing the bag).

4. I added the water from step 3 to my boil kettle and repeated until I had 6 gallons of pre-boil volume in my boil kettle.

5. 60 minute boil brought volume down to nearly 5 gallons.

EDIT: this way, I could do a full-boil 5 gallon batch with my 7.5 gallon turkey fryer.

That's fine. You can also just add all of the water from step2 into an ale pail (if the separate pot isn't large enough) and then put the grain bag in the pail, stir, pull it out and squeeze, then add that to the kettle. That's less steps than repeatedly pouring water over the grain bag, at least.

 

[LLBeanJ]

That's definitely one way to skin the cat. Did you hit your expected OG?

 

[Ridire]

That's definitely one way to skin the cat. Did you hit your expected OG?

I did not. However, I did not read enough about BIAB before doing that batch and had the LHBS guys crush my grains. It is my understanding that they crush very coarse so as not to get the mash tuns plugged up with hulls. I have subsequently purchased my own grain mill and will crush a bit finer to see if my efficiency goes up.

I think I was at around 63% efficiency, according to BeerSmith. I am basing my next brew on an expected efficiency of 70%, crushing the grain really fine, and seeing where I get.

EDIT: still ended up with the best beer I've ever brewed, a 5% ABV blonde. I also was too timid about squeezing the bag [insert immature joke here]. I have developed a fix for that, too, involving the lid from a pot that is nearly the same OD as the ID of the Ale Pail.

 

[woozy]

So I am trying to wrap my head around this issue. If I want to brew something like Centennial Blonde in a 23Q vessel with BIAB, calculators/calculations are showing I need 8 gallons of water to end up with 5.5 in my fermentor, to end up with 5 gallons of beer.

Why can't I just mash into the 5 gallons or even 1.25q/lb, and then add water to get it to 5 gallons of wort to boil? (very little boils off on the stove)

I mean, the amount of sugars is the same, no?

Yes! I think you are absolutely right! Although there's a minimum. With, say 10 lbs of grain at 2 qts/lb is 4 gallons. Ouch! No sparging. But dunking can make up for it. At least that's my opinion.

If you just add straight water to the boil you'll likely wind up with lower efficiency due to not doing the full-volume mash. However, if you can do some sort of sparge, say by dunking the grains in the water you want to add in, or pouring the water over the grains before adding it to the BK, you'll likely improve your efficiency beyond what you would have gotten had you done a full-volume mash.

He's doing a full-volume mash. Just not a "full-volume sparge". I think the "dunk sparging" will make up for it.

This. Because you get more sugar with a "rinse" of the grain rather than just topping off with water, your efficiency will be low. If you don't care, adjust the recipe to use more grain and cheers.

True but the question is how much water is needed for a sparge. Suppose 12 lbs of grain at 1.5 quarts a lb. That's 4 1/2 gallons for the mash. An 8 gallon pre-boil allows 3 1/2 gallons to sparge. A 5 gallon allows only 1/2. He'd have to make up by dunking.

Is there a way to calculate exactly how much more grain I would need to add to the Centennial Blonde recipe then, if I am planning on using the 23L kettle and some type of dunk sparge? Let me rephrase, I am sure there *is* but maybe I am just not seeing how to do it.

Well, you have to know how inefficient dunk sparging in less water is and no-one seems to know that.

You can experiment. Add 25% more grain (probably too much). Check your pre-boil gravity. If it's too high, you just toss out the some of the wort.

(The trick is Volume * Gravity Points = constant. This is true pre-boil, post-boil and after top off. Thus if you target o.g is 1.050 and your pre-boil 5 gallon gravity is 1.060; the 5*60 is 300, you *want* 5 * 50 is 250, so you toss out 5/6 to have 4 1/6 * 60 = 250. And top off to 5 *pre-boil* to have 5 gallons at 1.050.)

Doing no sparge or a dunk sparge probably puts you in the 65% efficiency range, just a shot-in-the-dark here.

If you have enough water it puts you in the 80 to 85% range. With not enough water... don't know.

But he can shoot low. Then if his pre-boil gravity at 5 gallons is *higher* than his targeted gravity at 5 gallons, he can ditch enough until Volume * GP = 5 * O.G gravity points.

(Gravity points, btw, are that "bits after the 1". e.g. 1.050 gravity ~ 50 gravity points. 1.035 ~ 35 points and so on.)

 

[woozy]

I only have one BIAB under my belt but here is what I did (any more experienced guys please tell me if there is a problem with this - beer turned out great):

1. mashed in my boil kettle with 1.5 qts of water per 1 lb. of grain (roughly 5 gallons for my grain bill).

2. In a separate pot, I heated 3-4 gallons of water to around 170 degrees.

3. After the 60 minute mash, I removed my bag from the boil kettle, placed it in a 7 gallon Ale Pail and rinsed it with some of my 170 degree water (squeezing the bag).

4. I added the water from step 3 to my boil kettle and repeated until I had 6 gallons of pre-boil volume in my boil kettle.

5. 60 minute boil brought volume down to nearly 5 gallons.

EDIT: this way, I could do a full-boil 5 gallon batch with my 7.5 gallon turkey fryer.

I have two (successful) under my belt. A two gallon batch. I mashed 4.1 lbs of grain in the *entire* pre-boil volume, 3.1 gallons, rose to 170, dunked. Boiled down to 2 gallons. 78-80% efficiency. My O.G. slightly over.

 

[jrodder]

Yes! I think you are absolutely right! Although there's a minimum. With, say 10 lbs of grain at 2 qts/lb is 4 gallons. Ouch! No sparging. But dunking can make up for it. At least that's my opinion.




He's doing a full-volume mash. Just not a "full-volume sparge". I think the "dunk sparging" will make up for it.



True but the question is how much water is needed for a sparge. Suppose 12 lbs of grain at 1.5 quarts a lb. That's 4 1/2 gallons for the mash. An 8 gallon pre-boil allows 3 1/2 gallons to sparge. A 5 gallon allows only 1/2. He'd have to make up by dunking.



Well, you have to know how inefficient dunk sparging in less water is and no-one seems to know that.

You can experiment. Add 25% more grain (probably too much). Check your pre-boil gravity. If it's too high, you just toss out the some of the wort.

(The trick is Volume * Gravity Points = constant. This is true pre-boil, post-boil and after top off. Thus if you target o.g is 1.050 and your pre-boil 5 gallon gravity is 1.060; the 5*60 is 300, you *want* 5 * 50 is 250, so you toss out 5/6 to have 4 1/6 * 60 = 250. And top off to 5 *pre-boil* to have 5 gallons at 1.050.)



If you have enough water it puts you in the 80 to 85% range. With not enough water... don't know.

But he can shoot low. Then if his pre-boil gravity at 5 gallons is *higher* than his targeted gravity at 5 gallons, he can ditch enough until Volume * GP = 5 * O.G gravity points.

(Gravity points, btw, are that "bits after the 1". e.g. 1.050 gravity ~ 50 gravity points. 1.035 ~ 35 points and so on.)

Awesome response, thank you. This jibes with what I had going on in my head. All this being said, I have figured that what really needs to happen is I need to convert the keg I have in the garage to a keggle. Another 250 bucks down the drain (I need a good burner too) but after the SWMBO is done yelling at me, I'll have plenty of brew time in the garage.

I am tempted to just grab a paint strainer bag and experiement a bit. The key is this really:

Well, you have to know how inefficient dunk sparging in less water is and no-one seems to know that.

You can experiment. Add 25% more grain (probably too much). Check your pre-boil gravity. If it's too high, you just toss out the some of the wort.