Large Grail Bill...

[Ungoliant]

Okay, folks, I'm looking at doing an Old Ale (5 Gal), and the grain bill ended up being 18 lbs. I have recently been in a recipe development kick, and got so ahead of myself I didn't really consider that my 10gal Kettle may not be able to fit a full-volume mash for this and other high-gravity brews. I've seen some folks talk about rinse-sparging and other stuff to hit your full volume and still get good efficiency.

Can y'all either link to or describe (in detail) some methods I could use to get a good mash in and still hit full volume, without necessarily having to just top-up?

 

[dwhite60]

Do a half batch. Than another half batch. Could break it up and do two different yeasts.

All the Best,
D. White

 

[doug293cz]

Use the calculator here to figure out how much strike water you can use for your mash without overflowing your kettle. Then use the balance of your water to sparge with.

Brew on

 

[TexasWine]

Can y'all either link to or describe (in detail) some methods I could use to get a good mash in and still hit full volume, without necessarily having to just top-up?

You should also consider reducing your volume to something like four gallons.

But back to sparging, there are two primary methods folks use with BIAB; dunk and pour over. Dunk means you pull the bag out of the kettle and dunk it in another vessel containing more water. Most folks give the bag a little squeeze to drain some wort into the kettle before transferring the bag to the dunking vessel. The dunking vessel can be another kettle, a bucket, anything really, as long as it's big enough to hold the water and grain.

The pour over method is just that. Pour some water over it. Some folks pour water right on the bag as it hangs over the kettle. Others use a steamer basket to lift the bag, open up the bag and pour directly into the grain. And still others use things like buckets with tiny little holes that sit on top of the steamer basket + grains. The water slowly trickles through the grain.

And a couple of things that are common to both methods concern the sparge water. First, concerning how much water to use, common practice is to use as much water in the mash as you can, leaving just enough freeboard too stir. Use the remaining water to sparge. And then there's water temp. Room temp is fine, but it will slow down your brew day because your time to reach boiling temps will be lengthened.

Hope this answers your questions.

 

[doug293cz]

^^ +1 ^^

Brew on

 

[Ungoliant]

Use the calculator here to figure out how much strike water you can use for your mash without overflowing your kettle. Then use the balance of your water to sparge with.

Brew on

I guess I'm gonna end up trying a dunk sparge for this one.

Well, that is a pretty easy to use calculator, way better than any I've used (input effort vs. result detail). However, the results are a bit to chew on. I get most of it, but I'm not deep enough in to brewing to start talking about mash analysis. So, let me give you some input, and if you don't mind, help me understand some of this a bit better (or point me somewhere that can).

According to the Brewer's Friend recipe calc, the OG of this batch should be 1.098. With the following inputs, the calc tells me my post-boil SG will be 1.0821.

Here are my inputs:
Target batch size is 5.5, hop bill 3 oz, 90 min. boil, grain temp 70, sparge volume 2.11 (simple biab told me I needed 10.24 gallons mash water, yours said I needed 8.13g, so I split the difference), kettle is 13.8 inches wide, 0 kettle loss, assuming ~75% efficiency (it's high gravity, last batch was ~75%), left hop absorption at 0.0365, grain bill is 18.05 lbs, 0 dry hops, boil-off 1.5, mash temp 153, 10.7 gal kettle, left mash tun losses at 0, trub loss 0.5, and my last two batches had a grain absorption rate of 0.036.

 

[doug293cz]

I guess I'm gonna end up trying a dunk sparge for this one.

Well, that is a pretty easy to use calculator, way better than any I've used (input effort vs. result detail). However, the results are a bit to chew on. I get most of it, but I'm not deep enough in to brewing to start talking about mash analysis. So, let me give you some input, and if you don't mind, help me understand some of this a bit better (or point me somewhere that can).

According to the Brewer's Friend recipe calc, the OG of this batch should be 1.098. With the following inputs, the calc tells me my post-boil SG will be 1.0821.

Here are my inputs:
Target batch size is 5.5, hop bill 3 oz, 90 min. boil, grain temp 70, sparge volume 2.11 (simple biab told me I needed 10.24 gallons mash water, yours said I needed 8.13g, so I split the difference), kettle is 13.8 inches wide, 0 kettle loss, assuming ~75% efficiency (it's high gravity, last batch was ~75%), left hop absorption at 0.0365, grain bill is 18.05 lbs, 0 dry hops, boil-off 1.5, mash temp 153, 10.7 gal kettle, left mash tun losses at 0, trub loss 0.5, and my last two batches had a grain absorption rate of 0.036.

I'm not the author of the calculator. @pricelessbrewing is the author. I did help priceless with the Mash Analysis math.

One item that is probably confusing you is the "Conversion efficiency" input. This is not your mash or brewhouse efficiency. Conversion efficiency is the percentage of available starch in the grain that actually gets converted to sugar in the mash. Lauter efficiency is the percentage of the sugar that is created in the mash that actually ends up in the kettle. Mash efficiency is conversion efficiency times lauter efficiency. In a well conducted mash, conversion efficiency should be 95% or better. When I plug your numbers into the calculator, but use 95% conversion efficiency, I get a projected post boil SG (OG) of 1.102. Lauter efficiency is 90.3, and mash efficiency is 85.8%.

The brewing water volume difference is because Simple BIAB Calculator is assuming a grain absorption of about 0.125 gal/lb. This value is typical for a batch sparge process in a traditional mash tun, but is high for BIAB. Your stated grain absorption of 0.036 gal/lb is unbelievably low. The lowest credible BIAB grain absorption I have seen is 0.045 gal/lb, and that requires some serious squeezing. I suspect you may have some volume measurement or calculation errors in order to get to 0.036.

Brew on

 

[Ungoliant]

That definitely explains a lot, in regards to the calculator. Thanks for the explanation.

My math might be wrong on the grain absorption, but I've done a handful of BIAB batches so far, and my grain absorption has been lower and lower each time. My first BIAB I had something like .0556 gal/lb, and I've drained longer and squeezed much harder in subsequent batches. I don't play around when it comes to squeezing the bag. Next time I'll have to break out the tape measure or something for a more accurate reading between my kettle's hash marks.

What I do is Strike Volume - Post Drain/Squeeze Volume, then divide the difference by the grain bill in pounds.

I use this post as a reference:
https://www.homebrewtalk.com/showpost.php?p=5655930&postcount=1

 

[wilserbrewer]

Excellent information above. FWIW i am a fan of the "pour over" sparge. While it may or may not be as efficient as a thorough batch sparge, I find it to be a heck of a lot easier both physically and mentally.

With the bag suspended above the kettle on a rathcet pulley, one just continues sparging until pre boil volume is realized in the brew kettle. No moving the grain to another vessel, and no attempt at calculating an unknown anticipated result...so easy almost "idiot proof"

Cheers

 

[doug293cz]

That definitely explains a lot, in regards to the calculator. Thanks for the explanation.

My math might be wrong on the grain absorption, but I've done a handful of BIAB batches so far, and my grain absorption has been lower and lower each time. My first BIAB I had something like .0556 gal/lb, and I've drained longer and squeezed much harder in subsequent batches. I don't play around when it comes to squeezing the bag. Next time I'll have to break out the tape measure or something for a more accurate reading between my kettle's hash marks.

What I do is Strike Volume - Post Drain/Squeeze Volume, then divide the difference by the grain bill in pounds.

I use this post as a reference:
https://www.homebrewtalk.com/showpost.php?p=5655930&postcount=1

That's the correct basic math, but to get accurate results you need to correct all volume measurements to the same reference temperature. If you measure your strike water at 68°F, and your pre-boil volume at 180°F, then you will get an unrealistically low grain absorption. Let's do an example:

12 lbs of grain
7.42 gal of strike water @ 68°F
6.70 gal pre-boil wort @ 68°F
Grain Absorption = (7.42 - 6.70) / 12 = 0.72 / 12 - 0.06 gal/lb​

But, if that 6.7 gal of wort was heated to 180°F, it would have a volume of 6.89 gal, and the calculation would look like this:

Grain Absorption = (7.42 - 6.89) / 12 = 0.53 / 12 = 0.044 gal/lb​

The Pricelessbrewing calculator uses a 68°F reference temperature.

The example shows that small errors in either volume measurement can lead to relatively large errors in the calculated grain absorption.

Brew on

 

[doug293cz]

Excellent information above. FWIW i am a fan of the "pour over" sparge. While it may or may not be as efficient as a thorough batch sparge, I find it to be a heck of a lot easier both physically and mentally.

With the bag suspended above the kettle on a rathcet pulley, one just continues sparging until pre boil volume is realized in the brew kettle. No moving the grain to another vessel, and no attempt at calculating an unknown anticipated result...so easy almost "idiot proof"

Cheers

Yeah, the pour over is easier to execute, and it's what I do when I have to sparge.

The pour over however is impossible to simulate accurately. I do the simulations to provide a better understanding of how the processes work, and to provide realistic estimates of what is possible. You can do worse than the simulations but you can't do better. If you hit the simulated values, you are getting the most possible out of your process. If you are not getting close to the simulated values, then there is room for improvement. But, that doesn't mean you should change anything if you are satisfied with the results you are getting. Maximum efficiency isn't the most important goal in brewing (unless you want it to be.)

Brew on

 

[TallDan]

 

[AnOldUR]

With the bag suspended above the kettle on a rathcet pulley, one just continues sparging until pre boil volume is realized in the brew kettle. No moving the grain to another vessel, and no attempt at calculating an unknown anticipated result...so easy almost "idiot proof"

This idiot has yet to figure out a way to know how much more wort will come from the bag after I stop the pour over and squeeze. Guess and adjust the boil is the best I can do (and that seems to works just fine).

 

[Onkel_Udo]

This idiot has yet to figure out a way to know how much more wort will come from the bag after I stop the pour over and squeeze. Guess and adjust the boil is the best I can do (and that seems to works just fine).

Umm, all of it. Hang your bag until bascially nothing but a trickle (20 =minutes?) is coming out while you wait for boil to commence...at that point, even if you squeeze like the dickens, you are likely to get a whopping 1-3 cups more...so don't squeeze. Measure your kettle volume and sparge with as much as you need to reach pre-boil volume. Your grain is already saturated and will not absorb any more.

So let's say desired pre-boil volume is 7.5 gallons. After 20 minutes of hanging you have 5.5 gallons in the pot. Regardless of dunk or pour over sparge, sparge with 2 gallons.

 

[Ungoliant]

That's the correct basic math, but to get accurate results you need to correct all volume measurements to the same reference temperature. If you measure your strike water at 68°F, and your pre-boil volume at 180°F, then you will get an unrealistically low grain absorption. Let's do an example:

12 lbs of grain
7.42 gal of strike water @ 68°F
6.70 gal pre-boil wort @ 68°F
Grain Absorption = (7.42 - 6.70) / 12 = 0.72 / 12 - 0.06 gal/lb​

But, if that 6.7 gal of wort was heated to 180°F, it would have a volume of 6.89 gal, and the calculation would look like this:

Grain Absorption = (7.42 - 6.89) / 12 = 0.53 / 12 = 0.044 gal/lb​

The Pricelessbrewing calculator uses a 68°F reference temperature.

The example shows that small errors in either volume measurement can lead to relatively large errors in the calculated grain absorption.

Awesome feedback. So you're saying I'd get a more accurate number by measuring Strike and Post Drain/Squeeze volumes at the same temperature, correct? Or are we saying that 68°F is the "gold standard" and I should correct for that? I'm brewing this Old Ale today so I'm looking at getting some accurate numbers on this, considering that I definitely was brushing my shoulder off when I did the math last batch.

 

[Bellybuster]

This idiot has yet to figure out a way to know how much more wort will come from the bag after I stop the pour over and squeeze. Guess and adjust the boil is the best I can do (and that seems to works just fine).

wow.... harsh and uncalled for... the answer is common sense. idiot? really?

 

[TallDan]

wow.... harsh and uncalled for... the answer is common sense. idiot? really?

I think he was referring to himself, not anyone else.

 

[Onkel_Udo]

wow.... harsh and uncalled for... the answer is common sense. idiot? really?

Uh, yeah, I took it as inward directed sarcasm as well.

 

[AnOldUR]

Measure your kettle volume and sparge with as much as you need to reach pre-boil volume. Your grain is already saturated and will not absorb any more.

Duh! I've been doing this with 3V batch sparging for years, but for the few BIAB's that I've done it never occurred to me to check the volume before starting pour-over.

I think he was referring to himself, not anyone else.

Yes. I've yet to master sarcasm on the webs. Sorry to offend.

 

[doug293cz]

Awesome feedback. So you're saying I'd get a more accurate number by measuring Strike and Post Drain/Squeeze volumes at the same temperature, correct? Or are we saying that 68°F is the "gold standard" and I should correct for that? I'm brewing this Old Ale today so I'm looking at getting some accurate numbers on this, considering that I definitely was brushing my shoulder off when I did the math last batch.

Oh crap! I wrote a detailed answer to this, and it's not here. I must have hit the back button rather than the post button. Who can I blame for this obvious operator error? So, here goes again:

You don't need to measure everything at the same temperature, you just need to adjust the measurements for thermal expansion back to a consistent reference temperature. I believe ASBC (American Society of Brewing Chemists) and ICUMSA (International Commission for Uniform Methods of Sugar Analysis) use 20°C (68°F) for a reference temperature. I also use 68°F as a reference temperature in my mash/lauter simulator, and @pricelessbrewing also uses this as a reference temp in his on-line calculator.

To adjust a volume measurement at T[hot] to T[ref] use the following formula:

Vol@T[ref] = Vol@T[hot] * Water_Density@T[hot] / Water_Density@T[ref]​

You can find a good equation for water density as a function of temperature in this post. If you want to geek out, you can read the entire thread, and find out more than you ever wanted to know about water and wort density.

Brew on

 

[Bellybuster]

Yes. I've yet to master sarcasm on the webs. Sorry to offend.

Coolio, I've had a few statements taken wrong over the years, my apologies

 

[iijakii]

I tried the dunk sparge once and learned the hard way that my bag full of 20lbs of grain doesnt exactly fit in a 5gal bucket!

 

[Onkel_Udo]

I tried the dunk sparge once and learned the hard way that my bag full of 20lbs of grain doesnt exactly fit in a 5gal bucket!

Yeah...we all learn that one the hard way...

 

[wilserbrewer]

I tried the dunk sparge once and learned the hard way that my bag full of 20lbs of grain doesnt exactly fit in a 5gal bucket!

Yea, 20 lbs should fit in a five gallon bucket, it's just difficult to do the required gymnastics with wort all over the floor lol.

Dunk sparging is likely a bit more manageable with smaller grain bills. I prefer a small pour over to adjust to preboil volume. Perhaps not the most efficient, but so damn easy the way I like it.

 

[iijakii]

Oh yeah, wasn't due to volume I don't think -- just shape of how it hangs in the bag. I tried setting it in the bucket but the bag made too much contact with the bucket rim, wort poured down the sides of hte bucket at those points. Probably could have just shoved it in there but I went back to hanging after that. I get a solid 70% eff on even large bills, so not to worried. I still havent tried a pour sparge on this system. Helped a lot back when I had a Brutus 20 though.

 

[Ungoliant]

Oh crap! I wrote a detailed answer to this, and it's not here. I must have hit the back button rather than the post button. Who can I blame for this obvious operator error? So, here goes again:

You don't need to measure everything at the same temperature, you just need to adjust the measurements for thermal expansion back to a consistent reference temperature. I believe ASBC (American Society of Brewing Chemists) and ICUMSA (International Commission for Uniform Methods of Sugar Analysis) use 20°C (68°F) for a reference temperature. I also use 68°F as a reference temperature in my mash/lauter simulator, and @pricelessbrewing also uses this as a reference temp in his on-line calculator.

To adjust a volume measurement at T[hot] to T[ref] use the following formula:

Vol@T[ref] = Vol@T[hot] * Water_Density@T[hot] / Water_Density@T[ref]​

You can find a good equation for water density as a function of temperature in this post. If you want to geek out, you can read the entire thread, and find out more than you ever wanted to know about water and wort density.

Brew on

Unfortunately, that math is a bit more complicated than my current skill level. I'll have to sit down and tackle this in a while.

 

[Ungoliant]

Well, I should specifiy that the math in your reference thread is a little brainier than I can handle at the moment. I'm about to sit down and figure out what I did this time (got it on boil, nice and steady)