Mash eff calculation check

[pretzelb]

I'm trying to check my calculations on my last brew and wanted to see if I'm doing this correctly. Last brew was a high gravity 5g batch. For the PPG I used the numbers of 13 lbs Wheat Malt @ 37, 6 lbs of 2 row @ 36, and 1 lb of crystal 40 at 34. Max points was 731. My pre-boil volume was 7.5g which calculates to 97.47 at 100% (731/7.5 * 1). My actual gravity was 1067 which I think means I had 69% mash efficiency (67/97). Does that sound about right?

I was originally happy with the gravity readings until I started to check the max amount and then find the percentages. But this is a lot of grains and I did a full volume mash without any sparge water.

 

[enkamania]

I threw your numbers in http://www.brewersfriend.com/brewhouse-efficiency/ and got 67%. With wheat I usually get a little lower efficiency. The thing with efficiency is to shoot for consistancy.

 

[1MadScientist]

I'm getting a 72% into boil efficiency which is good, seeing that the BIABacus is estimating a 75.5%

 

[dmtaylor]

Your numbers are correct. And they make perfect sense if you didn't sparge at all. This was a big beer so there's a lot of sugars that got permanently tied up in the spent grains. That's the reason for it. If you had only planned on making a regular strength beer around 1.055 or whatever, your efficiency would probably have been much higher.

Cheers.

 

[dmtaylor]

Or no, wait a second... I'm causing confusion again. I was talking more about lauter efficiency or brewhouse efficiency, not mash efficiency specifically. If you had a good crush then your mash efficiency should have been much higher, close to 90% or more. So, maybe you didn't crush enough. It happens a lot with wheat, which has smaller kernels than barley. Set the mill gap a little tighter, or double crush. Sorry for confusion.

 

[pretzelb]

Or no, wait a second... I'm causing confusion again. I was talking more about lauter efficiency or brewhouse efficiency, not mash efficiency specifically. If you had a good crush then your mash efficiency should have been much higher, close to 90% or more. So, maybe you didn't crush enough. It happens a lot with wheat, which has smaller kernels than barley. Set the mill gap a little tighter, or double crush. Sorry for confusion.

The problem is my system is an electric single vessel with a solid sided basket that re-circulates to maintain mash temp. If I crush too much then I have trouble with re-circulation. If I don't crush enough it seems like I'm losing too much potential sugars. My only options for sparge are just saving a few gallons instead of doing a full volume mash but that isn't always easy when doing a high gravity 5g batch in a 20g kettle.

I'm also a bit concerned that I'm getting different responses for the numbers. BrewersFriend appears to be giving BH efficiency instead of just a mash efficiency so that would explain some of it. I'll have to see if I can enter this into BIABacus to see why it feels the numbers are higher.

 

[dmtaylor]

The only way to know for sure what the PPG is for each malt is to read it on the bag. Otherwise all these softwares can do is to use guesses as to the average values. That's why they're slightly different. Consistent and reasonably close, but slightly different.

 

[MerlinWerks]

My only options for sparge are just saving a few gallons instead of doing a full volume mash but that isn't always easy when doing a high gravity 5g batch in a 20g kettle.

You can try a longer boil which will require more water initially, that way you can reserve a gallon or so to sparge and not have a super thick mash.

See HERE...

When I go north of 1.068 or so I calculate for a 120 min boil.

 

[pretzelb]

The only way to know for sure what the PPG is for each malt is to read it on the bag. Otherwise all these softwares can do is to use guesses as to the average values. That's why they're slightly different. Consistent and reasonably close, but slightly different.

That would make sense for the tools that use their own values for the grains. But it still surprises me to not have consistency in the terms and calculations.

And to go back and be technical I think what my post is really calculating is what some call conversion efficiency. With a full volume mash you don't really get a lauter, then again if you squeeze then maybe you could call that the lauter?

It is frustrating but I think the new data I'm collecting in a spreadsheet outside of BeerSmith will help.

 

[pretzelb]

You can try a longer boil which will require more water initially, that way you can reserve a gallon or so to sparge and not have a super thick mash.

See HERE...

When I go north of 1.068 or so I calculate for a 120 min boil.

With my single vessel system the best sparge I could do is dumping water over the grain basket as it is suspended above the kettle. This should improve things a bit but I am not sure it would be enough to justify a 120 minute boil.

But I do think it is something I need to try in the future. I'm trying to keep things simple for now. I've nearly got BeerSmith working for the full volume mash profile. And I need to make sure I have the re-circulation down before I go messing with my water to grain ratios.

What I need is more kegs to store all these "tests" I have planned.

 

[MerlinWerks]

That's what I do with my Brew-Boss system and basket from Arbor-Fab. I would always miss my OG on bigger brews before going with a longer boil and more water. I usually only need to reserve a gallon to sparge with and still have enough to recirculate. Now I'm usually a couple points over.

To save time once you are dialed in to your system you can always boil harder at first, then cut back to your "normal" boil strength. So even with a boil volume calculated for 120 min, boil harder for 30 min then resume a normal boil for 60 for a net 90 min boil. Many different ways you can approach it, but unfortunately there's no free lunch

 

[doug293cz]

You did about as well as possible. I get your conversion efficiency at essentially 100%, and your lauter efficiency at about 70%. Mash efficiency is also about 70%, as mash efficiency equals conversion efficiency times lauter efficiency. I would need more accurate/precise numbers for volumes and grain potentials to get a better estimate. For that size grain bill, pre-boil volume, and no sparge, your lauter efficiency can't get much higher than 70%. To get higher you would need to reduce your grain absorption (by squeezing the grain bed somehow), or upping your pre-boil volume significantly.

Brew on

 

[pretzelb]

You can try a longer boil which will require more water initially, that way you can reserve a gallon or so to sparge and not have a super thick mash.

See HERE...

When I go north of 1.068 or so I calculate for a 120 min boil.

i read that article a few times but I was stuck trying to figure out how to calculate for a higher volume sparge. I assume if you enter 120 minute boil into the software of your choice the water adjustments are made for you.

 

[doug293cz]

i read that article a few times but I was stuck trying to figure out how to calculate for a higher volume sparge. I assume if you enter 120 minute boil into the software of your choice the water adjustments are made for you.

The problem with trying to maintain constant lauter (and mash) efficiency with increasing grain bill weights, is that you have to increase your pre-boil volume proportionately to the increase in grain wt. If you want to do an 18 lb grain bill at the same efficiency as a 9 lb grain bill, you have to double your pre-boil volume. For example, if you normally target 6.75 gal pre-boil to get 5.5 gal post boil after a 1 hour boil (1.25 gal/hr boil off) and want to double your grain bill, then you need to target 13.5 pre-boil, which would require a boil off of 8 gal. At 1.25 gal/hr this would take 6.4 hrs. This is totally impractical for most brewers.

A better way to deal with the decreasing efficiency is to figure out how much your efficiency is expected to drop, and then adjust your recipe based on the lower projected efficiency. The chart below can help you estimate a projected efficiency. Determine which curve most closely matches your efficiency at your typical grain wt to pre-boil volume ratio. Then move along that curve to the grain wt to pre-boil volume ratio for your planned "big" beer.



Brew on

 

[MerlinWerks]

i read that article a few times but I was stuck trying to figure out how to calculate for a higher volume sparge. I assume if you enter 120 minute boil into the software of your choice the water adjustments are made for you.

Yes, I use Beersmith and it will adjust the amount strike water according to boil length.

If you are doing BIAB, for a 120 min boil I think you would simply add your one hour boil-off volume to the total volume you calculate for a 60 min boil.

To give you an example of how all this worked for me, the first time I brewed a Stone Ruination clone:

16 lb. grist
Est OG 1.074
Meaasured OG 1.063
60 min boil
8.9 gal strike water
BIAB Mash

Second time:

16 lb. grist
Est. OG 1.075
Measured OG 1.075
120 min boil
9.6 gal strike water (1 gal reserved for pour over sparge after initial drain)
BIAB Mash

Perhaps it was just a fluke, but for any subsequent brews where I was shooting for an OG of 1.068+, a small pour over sparge got me there. In the interest of full disclosure I don't brew many big beers and haven't tried to go over 1.080 so a combination of a sparge and more grain may be required to get there, but this is what has worked for me...

Funny thing is, I actually preferred the first batch more