Efficiency for higher gravity

[mggray87]

I am tackling a very high 1.100-1.104 gravity brew saturday. Never attempted this high before. My last two 7% beers were 75% efficiency all said and done. Should i roll with it and keep it at 75% or lower to 70% with recipe. I dont mind if the outcome is under the 10% and is 9 or even 8. but if im expected to see maybe a 10% drop. 70% would atleast cushion it slightly.

I plan on trying to double mill for the first time for my Brew in a basket to maybe cushion slightly.

anyway I have both ways all set up and the brewing salts for both already done. just wondering if leaving it at 75% isnt smart. I guess either way saturday Ill get an idea on my system how the High gravity BIAB is gonna work for me. full volume mash.

 

[VikeMan]

All else being equal, your mash efficiency will be lower with a larger grain bill. How much lower will depend on your equipment and process. But as a swag, I'd probably expect roughly 6-7% lower mash efficiency for the kind of scale up you're looking at (assuming a no-sparge system).

 

[mggray87]

All else being equal, your mash efficiency will be lower with a larger grain bill. How much lower will depend on your equipment and process. But as a swag, I'd probably expect roughly 6-7% lower mash efficiency for the kind of scale up you're looking at (assuming a no-sparge system).

ok ill just go with 70% instead of my regular 75% and try for the first time a double pass on the mill and ill see what happens.....

 

[user 246304]

Good to read this - I am at about 72%, and was going to drop it 10 pts, to 62%, for an 1848 Barclay Perkins RIS, intended OG 1.104. It's been many years since my last RIS, and I don't have the log unfortunately.

 

[doug293cz]

If you have data from previous brews that includes:

• Grain bill weight
• Grain bill weighted average extract potential (a default value can be used here if data doesn't exist)
• Strike water volume
• End of mash SG (after a good stirring)

We can calculate your typical conversion efficiency. Lauter efficiency can be predicted as a function of process, grain bill weight, and pre-boil volume. And since mash efficiency equals conversion efficiency times lauter efficiency, we can predict with good accuracy what your mash efficiency will be for a brew with a much larger than normal grain bill.

If your typical conversion efficiency is less than 100%, then double milling is likely to improve your conversion efficiency. If you are already ~100%, then double milling will not improve your mash efficiency.

Lauter efficiency drops off as the grain bill weight to pre-boil volume ratio increases (increasing grain weight for constant pre-boil volume.) This happens for all lautering processes roughly equally. Below is a chart that shows this effect:

My spreadsheet can do the mash and lauter predictions for you.

Brew on

 

[day_trippr]

fwiw, I do a 1.107 stout and Beersmith has consistently reported a mash efficiency of 75.5% and a BHE of 72%...

Cheers!

 

[doug293cz]

fwiw, I do a 1.107 stout and Beersmith has consistently reported a mash efficiency of 75.5% and a BHE of 72%...

Cheers!

What is your process?

Brew on

 

[day_trippr]

3v2p single tier herms, 45.5 pounds of malt, tight grind, underlet strike, fly sparge, 14% boil-off (14g preboil -> 12g cooled post boil). I lose another half gallon to kettle lautering (hops and cocoa goop in the kettle) and a gallon to fermentor goop putting ~10 gallons in kegs...

Cheers!

 

[doug293cz]

3v2p single tier herms, 45.5 pounds of malt, tight grind, underlet strike, fly sparge, 14% boil-off (14g preboil -> 12g cooled post boil). I lose another half gallon to kettle lautering (hops and cocoa goop in the kettle) and a gallon to fermentor goop putting ~10 gallons in kegs...

Cheers!

A good fly sparge will beat the solid green line in the chart I posted above. It's not likely that a basket system could do as well as a good traditional 3 vessel system.

Brew on

 

[mggray87]

I'm just gonna do the 70% recipe. And just see what it does. I'll learn for next time. 70% and double milling. I'll report back

 

[jerrylotto]

When I mash high gravity worts, I tend to do it in two stages. Stage 1 is all base malt using 50% of the weight of the overall grain bill then sparge. I collect the sparge runnings separately in a different vessel and make it up to a full strike volume by adding first runnings to it (if necessary). Finally, I mash the remaining base malt and all of the adjuncts in that new "strike wort", holding aside a second sparge volume of water at 170F to rinse down the secondary mash.

 

[kevin58]

I'm just gonna do the 70% recipe. And just see what it does. I'll learn for next time. 70% and double milling. I'll report back

I reduce my efficiency by 10% so I would go lower than that. If you are hell bent on using 70% then have some DME on hand as insurance.

 

[user 246304]

If you have data from previous brews that includes:

• Grain bill weight
• Grain bill weighted average extract potential (a default value can be used here if data doesn't exist)
• Strike water volume
• End of mash SG (after a good stirring)

We can calculate your typical conversion efficiency. Lauter efficiency can be predicted as a function of process, grain bill weight, and pre-boil volume. And since mash efficiency equals conversion efficiency times lauter efficiency, we can predict with good accuracy what your mash efficiency will be for a brew with a much larger than normal grain bill.

If your typical conversion efficiency is less than 100%, then double milling is likely to improve your conversion efficiency. If you are already ~100%, then double milling will not improve your mash efficiency.

Lauter efficiency drops off as the grain bill weight to pre-boil volume ratio increases (increasing grain weight for constant pre-boil volume.) This happens for all lautering processes roughly equally. Below is a chart that shows this effect:

View attachment 838761

My spreadsheet can do the mash and lauter predictions for you.

Brew on

Fantastic. Thanks doug. I'll have to chew on this but at first reading, awesome on the lauter efficiency curves. Kudos to you!

 

[dmtaylor]

I haven't read any of the other responses yet so here is my own answer in my own words:

If you want to maintain good efficiency with high gravity beers, the key concept is that you need to sparge more and boil longer versus a standard gravity batch. Sparging more will collect extra sugars, and when boiled longer will concentrate down where you want them, ending up with a standard batch size of X number of gallons that you want. Either that, or you can brew as normal, but plan on making a smaller batch size, again allowing those sugars you've collected to concentrate down more than normal.

If you enjoy the full volume mash (BIAB), plan to use a much bigger volume, collecting a heck of a lot more wort and boil longer. (EDIT: And by longer, I mean like 2 or 3 hours.) Otherwise your efficiency WILL suck. Expect an efficiency loss close to 10-20% if you don't collect extra wort and boil longer.

 

[mggray87]

I haven't read any of the other responses yet so here is my own answer in my own words:

If you want to maintain good efficiency with high gravity beers, the key concept is that you need to sparge more and boil longer versus a standard gravity batch. Sparging more will collect extra sugars, and when boiled longer will concentrate down where you want them, ending up with a standard batch size of X number of gallons that you want. Either that, or you can brew as normal, but plan on making a smaller batch size, again allowing those sugars you've collected to concentrate down more than normal.

If you enjoy the full volume mash (BIAB), plan to use a much bigger volume, collecting a heck of a lot more wort and boil longer. (EDIT: And by longer, I mean like 2 or 3 hours.) Otherwise your efficiency WILL suck. Expect an efficiency loss close to 10-20% if you don't collect extra wort and boil longer.

So if I normally boil 60 min and it's like 1.62g boil off. You mean what beersmith says. Add another 1.62g of volume to my mash and do a 2 hour boil???

 

[VikeMan]

Otherwise your efficiency WILL suck. Expect an efficiency loss close to 10-20% if you don't collect extra wort and boil longer.

Looking at his gravities, I don't see this getting to even 10% lower. Off the cuff, I predicited 6-7% in post #2, which I think is roughly what he'd see using @doug293cz's charts/spreadsheet.

So if I normally boil 60 min and it's like 1.62g boil off. You mean what beersmith says. Add another 1.62g of volume to my mash and do a 2 hour boil???

So even though I think @dmtaylor's estimate of your expected efficiency loss is a bit high, the idea of mashing with more water is certainly a valid way to improve mash efficiency. The reason is that mashing with more water makes a larger overall volume of wort, with the sugars/dextrins spread "thinner" in that larger volume. After runoff, the same volume of (non-usable) wort remains in the grains, but it's at a lower gravity. Less sugars/dextrins left in the grains means more sugars/dextrins in the kettle. (But then you have to boil longer.) Or you can take the mash efficiency hit and adjust the grain bill accordingly.

 

[Agent]

At some point (varies by person and system), the sheer volume of grain in the bag makes it harder to squeeze like normal. So you get the one-two punch of lower lauter efficiency due to concentration while simultaneously sliding down in efficiency due to higher than normal water content.

 

[mggray87]

Looking at his gravities, I don't see this getting to even 10% lower. Off the cuff, I predicited 6-7% in post #2, which I think is roughly what he'd see using @doug293cz's charts/spreadsheet.



So even though I think @dmtaylor's estimate of your expected efficiency loss is a bit high, the idea of mashing with more water is certainly a valid way to improve mash efficiency. The reason is that mashing with more water makes a larger overall volume of wort, with the sugars/dextrins spread "thinner" in that larger volume. After runoff, the same volume of (non-usable) wort remains in the grains, but it's at a lower gravity. Less sugars/dextrins left in the grains means more sugars/dextrins in the kettle. (But then you have to boil longer.) Or you can take the mash efficiency hit and adjust the grain bill accordingly.

Mind you, without the flame out honey

Well added. Beersmith says I want to be at 1.091.

Well, maybe I'll use the 70% eff instead of my normal 75%. And do double mill AND 120 min boil and just see where it goes.

 

[dmtaylor]

So if I normally boil 60 min and it's like 1.62g boil off. You mean what beersmith says. Add another 1.62g of volume to my mash and do a 2 hour boil???

It sure won't hurt. You'll cut your efficiency loss in half of whatever it would have been.

 

[kevin58]

So if I normally boil 60 min and it's like 1.62g boil off. You mean what beersmith says. Add another 1.62g of volume to my mash and do a 2 hour boil???

If you're using beersmith just increase your boil time and the software will adjust the volume required.

 

[mggray87]

If you're using beersmith just increase your boil time and the software will adjust the volume required.

I just did that and I'm ready for tomorrow. Question making boil 2 hours why did my ibu go from 98.1 to 108. The two hop additions still are set to 60 min and 15 min. But why would the ibu jump just By setting 2 hour boil. It shouldn't change as I'll just do a hour boil first then start my hour with hop additions??

 

[dmtaylor]

I just did that and I'm ready for tomorrow. Question making boil 2 hours why did my ibu go from 98.1 to 108. The two hop additions still are set to 60 min and 15 min. But why would the ibu jump just By setting 2 hour boil. It shouldn't change as I'll just do a hour boil first then start my hour with hop additions??

It's wrong. And in reality, you'll have about 90 IBUs in your final beer, as this is the ceiling for any beer. Physically only so much alpha acid can be isomerized without plating out somewhere in your fermenter or package before being served in your glass. So, with enough hops for >90 IBUs, regardless of the calculations, it won't matter AT ALL for THIS batch. You'll have about 80-90 IBUs.

 

[tracer bullet]

As another data point if it helps, I'm anywhere from 65-75% depending on my beer gravities. 65 for an Imperial, 75 for a light pale ale.

Of course sparging, mash temps, other things play a role but when all else is equal, the grain bill effect keeps me somewhere in between those numbers.

 

[youngdh]

I plan for reduced efficiencies and let my recipe calculate and increase the grain bill. Adding a couple of dollars of extra grain vs my time is worth it to me. I also set calculator for a 45 min mash which increases grain bill ever so slightly. If I’m short of SG at 45 min I just extend my mash time to pick up a couple of extra points. I use an Anvil Foundry with a bag in the malt pipe. I stir and lift pipe every 15-20 min to redistribute mash water from the dead space between malt pipe and outer wall (known issue with the Foundry even when recirculating). I also grind my malt fine. For low to mid gravity beers my mash efficiencies are in the low 70s.

 

[VikeMan]

I also set calculator for a 45 min mash which increases grain bill ever so slightly.

What calculator varies the grain bill size based on mash time? That doesn't make sense. The goal of every mash should be 100% conversion. And even if it weren't, where would any model get the data to predict a conversion % that varies with mash time?

 

[youngdh]

What calculator varies the grain bill size based on mash time? That doesn't make sense.

I use the BIABicus Spreadsheet for BIAB. Used it for years.

 

[DBhomebrew]

You're setting a 45m mash which decreases conversion efficiency which in turn requires a larger grain bill to hit your desired OG?

Hedging your bets in lieu of honing your process to ensure full and reliable conversion and lauter efficiencies?

 

[youngdh]

You're setting a 45m mash which decreases conversion efficiency which in turn requires a larger grain bill to hit your desired OG?

Hedging your bets in lieu of honing your process to ensure full and reliable conversion and lauter efficiencies?

I’ve honed my BIAB process as much as I can. BIAB is known for lower efficiencies so I just plan for it and move on . The beauty of this hobby is we have choices.

 

[DBhomebrew]

Indeed. FWIW, I also BIAB, with highly predictable mash efficiencies ranging 72-90 depending on pre-boil gravity.

 

[dmtaylor]

I usually mash 45 minutes and have seen brewhouse efficiency averaging >90% with a fine crush and collecting every drop of first runnings from the mash and every drop of the sparge, batch sparged with an even split volume 50/50 between first runnings and sparge. I've achieved the same with BIAB by sparging the bag (either dunk or "pseudo-fly"). Trouble is, stuck runoff sometimes (especially when not doing BIAB but even in a bag it can be painful sometimes), for which it was more reasonable in my view to dial back on the mill gap by a few mils to average 80-85% brewhouse instead.

Conversely, if you're not getting full conversion at 45 minutes, you might want to mill a little finer. You CAN get there. Then it's a matter of how fine is too fine for YOUR system before it gets stuck.

But if you don't care about full conversion... well you don't have to I suppose.