Yes, another thread about how to increase efficiency

[curtw]

Note: I'm specifically referring to "Pre-Boil Efficiency" as defined here: http://www.brewersfriend.com/brewhouse-efficiency/

I believe that I am not getting the sugars out of my grain bill, during mashing, that I think I should. I went back for my last several brew days, and I have pre-boil efficiency values ranging from 66% to 79%. I've been doing BIAB brews for the past year, and it's just not getting easier to predict what my OG will eventually be.

My set up and process:
- I'm doing "three gallon" brews
- Using an 8gal BK
- Grain bills from 7-10 lb, the vast majority of brews use 80+% 2-row
- My starting water volume is generally 5.9 - 6.3 gal: more water for larger grain bills + larger hop volumes
- My pre-boil volume is uniformly 5.4 - 5.7 gal.
- My mash temps have all been in the 148-151F range
- I do not sparge. I simply let the mesh bag drain for ~10 min after mashing, with some squeezing if I feel like it

I see far higher pre-boil efficiencies regularly reported on these forums. Note that I am *not* talking about brewhouse efficiency; I'm not concerned right now with whether my boil off is sufficient, or even what my OG is: just the gravity (temp adjusted) after mashing is complete.

What should I be doing different? Should I reduce my mash water, and use some of it for sparging? Should I let the mesh bag drain for an hour? Should I be putting it in a vise to squeeze every drop of liquid out?

Thanks!

 

[grrickar]

I'd try rinsing the grains. I don't use the BIAB method, but I rinse the grain bag when I do partial mashes. My thinking is some of the sugars get trapped in the grain and an rinse with hot water frees them. Then let the bag drain as normal. I'd be surprised if efficiency did not go up a couple points.

 

[doug293cz]

Note: I'm specifically referring to "Pre-Boil Efficiency" as defined here: http://www.brewersfriend.com/brewhouse-efficiency/

I believe that I am not getting the sugars out of my grain bill, during mashing, that I think I should. I went back for my last several brew days, and I have pre-boil efficiency values ranging from 66% to 79%. I've been doing BIAB brews for the past year, and it's just not getting easier to predict what my OG will eventually be.

My set up and process:
- I'm doing "three gallon" brews
- Using an 8gal BK
- Grain bills from 7-10 lb, the vast majority of brews use 80+% 2-row
- My starting water volume is generally 5.9 - 6.3 gal: more water for larger grain bills + larger hop volumes
- My pre-boil volume is uniformly 5.4 - 5.7 gal.
- My mash temps have all been in the 148-151F range
- I do not sparge. I simply let the mesh bag drain for ~10 min after mashing, with some squeezing if I feel like it

I see far higher pre-boil efficiencies regularly reported on these forums. Note that I am *not* talking about brewhouse efficiency; I'm not concerned right now with whether my boil off is sufficient, or even what my OG is: just the gravity (temp adjusted) after mashing is complete.

What should I be doing different? Should I reduce my mash water, and use some of it for sparging? Should I let the mesh bag drain for an hour? Should I be putting it in a vise to squeeze every drop of liquid out?

Thanks!

Your lauter efficiency (percent of sugar in mash extracted to BK) should be about 91% using some of the numbers you supplied. Let's assume 7 lbs of grain mashed in 5.9 gal of strike water, and 5.4 gal of wort to BK. If we assume sugar concentration is uniform throughout the mash, then you got 5.4/5.9 = 91.5% of the sugar in the mash into your BK.

Your lower yields may be because your conversion efficiency (percent of starch in mash converted to sugar) is much less than 100%. If you only converted 80% of the starch to sugar, then you mash/lauter efficiency would be 80% * 91% (0.80 * 0.915) = 73.2% (0.732).

Sparging and/or more aggressive squeezing would increase your lauter efficiency by removing a little more sugar from your mash. But you could get even better improvement by increasing your conversion efficiency. A finer grain crush is one easy way to improve conversion efficiency. With coarser crushes, a longer mash can improve conversion.

Brew on

 

[curtw]

I knew I'd forget something...

I crush grains at the LBHS, and having been burned before, I now pass all grains through the mill twice. Inspection tells me that the crush seems fine (though I'm no grizzled expert).

I'm also doing 60min mashes.

I'm doing water additions as per http://www.brewersfriend.com/mash-chemistry-and-brewing-water-calculator/ ; my last brew day had all "green stars" in the calculator, so I don't think my mash pH is too far off (details on request ).

Yes, I'm really trying to improve conversion efficiency. The way to do that is not obvious to me. Sparging/rinsing will possibly increase lauter efficiency, according to your explanation, which seems like a Good Thing, but not perhaps the lowest hanging fruit.

Thanks!

 

[GearDaddys]

Are you using any software? How far off are you on predicted preboil Gravity vs actual? My mash effiency went up when I started milling my own grains... With BIAB you can crush REALLY fine.. I think I have mine set to .02 inches.. One pass, lots of flour.. My last brew had a lower predicted og, (high water/grain ratio) and I wound up with 89 percent mash effiency.. May be worth getting yourself a mill!

 

[curtw]

Yes, I'm using brewersfriend, pretty happy with it. Its "All Grain OG, FG, ABV Calculator" for the brew I did on Saturday shows that my pre-boil eff was 70%, given my grain bill + my volume of wort into kettle.

If, during my recipe building, I use such an efficiency, then I'd hit my numbers, but I'm hoping to do better than 70% .

I really don't want to get my own mill. But you're perhaps onto something that the mill at the LHBS is fine for "normal" mashing, but too coarse for best-use BIAB. If that's the case, I better get used to having a low efficiency and hence overcompensate with more grain :-( .

Thanks,
Curt

 

[GearDaddys]

Out of curiosity... What was your predicted OG? I get different mash effiencies depending on the OG.. My bigger beers 1.070 and up mash effiencies are in the 70's I think, with brew house steady at 68.5.. But if I do a smaller beer 1.040 ish.. My effiencies are far greater.. You are right though about spending money on a mill.. You can buy a lot of "extra" grains to make up the diff for the 150 bones spent on a mill..

 

[m00ps]

that's a pretty wide range of efficiencies. Were all those BIAB using the same techniques, grain crush, etc?

I do 5gal BIAB and my efficiency is a bit on the lower end, usually about 67-68% every time, but I wouldn't change a thing. Getting consistent numbers is the primary goal IMO. That way, you can accurately design a recipe to your system. Hell my whole brewing process is based around that 67-68%. I don't mind paying an extra dollar or so for more malts if it means I know what my final product will be.

 

[Oginme]

My suggestions to consider:

As m00ps suggests, you really want to aim for consistency, so that your numbers will be predictable. If this leads to a higher overall efficiency, then that is fine.

First, I would recommend checking the pH of your mash. You don't need to be super accurate, but you want to know if you are in the 5.1 to 5.6 region for mashing.

Next, when you are adding your grains, stir like your life depends upon it! You will want to make sure that you have fully wetted out the grains and broken up any dough balls which have formed. Typically, I am stirring for 4 to 8 minutes during and after grain addition. Pretty vigorously.
I also stir up the grains after the mash just to make sure nothing has escaped me.

After that, pick a squeezing method and stick to it. I use a colander and press down with a plate to get as much of the sugars out of the grains that I can. Try to be consistent with it. Typically, I am pressing and tightening the bag around the grains until I can see very little wort wetting the surface of the bag as I squeeze. Based upon my calculations of water retained in the grain, I do a fairly good job at being consistent with it. If you just want to hang the bag over the kettle and allow it to drain for 10 minutes, that's fine too. Again, as long as you are consistent with how you are doing it.

Start there and see how you come out with the next couple of brews. For me, the addition of a sparge step always increases my lautering efficiency by right around 3%. Typically, I only use this now for higher OG recipes, as it makes up the difference from the drop in efficiency from the larger grain bill.

 

[Psych]

I have the same sort of thing, efficiency ranges greatly between like 60% and 80%, though I used to get over 90% occasionally. I've tried a variety of crushes, some very fine, some thicker. A variety of mash thicknesses, basically no consistency anymore across the board.

I figure it has to be something that isn't a static thing, ie: it's not my crush (cause the crush is a static thing, providing I don't change it across two batches), the mash time and thickness itself mostly static, so it must be the sugars just hanging onto the grains.

I'm going to try a thicker mash next time and do a hefty sparge step after mashing, maybe even seperate the grains into two bags so it's less of a hassle. Less of a bulky bag where grains can hide in the middle of this giant mess of wet sticky grain, avoiding my sparge water...

 

[agrazela]

Also agreed with m00ps.

I do 5gal BIAB, and I get 68-70% every time, regardless of my mash temp or water to grain ratio, and that consistency is more important to me than a few more percentage points.

I experimented with double-crushing grains at the LHBS, and even with pulverizing in a food processor or in the Ninja, and while that gained me a 2 or 3 percentage points, I found that it took a lot longer to drain the bag (as in, mesh clogged), and I got a lot more trub (so the "gains" were illusory anyway).

I experimented with pour-sparging and with dunk-sparging the bag, and while that also gained me 2 or 3 percentage points, I just don't find it to be worth the extra effort over just putting all the water into the mash.

I'd be willing to bet your broad range has mostly to do with consistency of crush. Like maybe your LHBS's rollers are loose or not well-aligned? Or someone's adjusting them differently between your uses of it?

 

[MindenMan]

I used to always do 90 minute mashes, but I started getting no reaction using iodine at 60 minutes, so I thought I was good to go. Wrong, I had to sparge like crazy just to hit my estimated O.G., and boil for what seemed like hours... So, I just brewed a batch of Brown Porter, waited 90 minutes, vorlauf'd, and sparged with 4 gallons of hot water. I hit my estimated pre-boil O.G., poured another gallon of water into the grain, stirred and walked away for 20 or so minutes, drained and got another gallon of 1.030 wort. There have been more there, but I was tired and cold.

EDIT: Due to a poor back, my ability to lift a pot full of grain and water is almost nonexistent. I do a different version of BIAB than most do, I heat my mash water, put in my paint strainers, add the grain while stirring like crazy, check the temp, and walk away for 30 min, check temp, and walk away for an hour more. Anyway, I then lift the grain bag out of my BK/mash tun, and put it into a 5 gallon bucket with a false bottom, sparge, and boil. This is the way I have done it the last few batches along with a 90 minute mash, and hit the numbers with wort left over. I freeze it until I need a starter wort, boil it down, and start all over again.

 

[vincentAlpha]

Even milling twice at my LHBS I've found a marked improvement in my efficiency using my own mill vs. the LHBS, at best I could hit 70% before my own mill, easily jumped 10% or more (still pinning down the efficiency). Might just be you've hit the upper limit of the conversion efficiency with your current setup. That being said, rinsing your grain is likely to help a bit.

 

[Gavin C]

Perhaps increasing your mashing temps to 152-154 range will give you better conversion as even if you lose some heat during the mash you will still be in the sweet spot throughout the duration of the sac rest. Just struck me that your mash temps are to the lower end of optimal. One more thing to consider. Are you insulating your mash?

 

[soccerdad]

I'm never in a hurry when I brew so a mash over 60 minutes does not bother me. Generally, since I check and stir at 20 minute intervals, when I hit 60 and if the temp is still good, I will say to myself, "let's do 20 more just to see what we get." And I usually get a few points. Then I will gather the bag at the top, turn on the heat on, and bounce the bag (to keep it off the kettle bottom) and mash out to 170. So I typically have grain in water for 70 to 90 minutes. Every beer is different, but I am generally getting kettle efficiency in a 75 to 85% range. Do you mash out at all?

 

[curtw]

Wow, thanks everybody for the great replies.

I'll try to summarize (and answer some questions):

1. My predicted OGs are in the .040 - .060 range. My pre-boil effs do not seem to correlate that well to the size of the grain bill / predicted OG.

2. I completely agree with m00ps that consistency is what I'm really interested in. For example, the brew from two days ago had an OG that was 10 points below what I was expecting -- my IPA turned into a PA .

3. I've never checked pH. I've got some strips around here somewhere, I should probably be using them. But I'm guessing that I'm in the ballpark; several brews were done with RO water and AJ deLange's primer at https://www.homebrewtalk.com/f128/brewing-water-chemistry-primer-198460/#post2310230 .

4. I have not been stirring madly at dough-in. It just never seemed like it would do any good, given my "mash thickness" of 24qt/9lb = 2.6qt/lb (i.e., sure seems wet enough to me!). But I will definitely try this.

5. I sure don't squeeze every drop of liquid from my grain bag. It seems that I'd be just sacrificing a few cups of wort, not truly hurting my eff. But I will try this too.

6. I've definitely been held captive by the LHBS mill. On a positive note, this mill has its setting locked in, not adjustable by customers, and so I'm betting that it's consistent for all my brews (from the second time on, when I started double crushing).

7. I've had higher mash temps, but (a) I'm trying to maximize attenuation, and so I've read that lower temps should help; and (b) I'm pretty sure that my thermometer reads low, so the "148-151F" is probably higher than this in reality. On my list is to buy a backup thermometer.

8. I have done longer mashes (75 and 90m) with mixed results, so I'm not convinced this would help.

9. I have never done a mashout. I'm lazy and the effectiveness seems in doubt.

What I really should do (sigh) is brew the same grain bill many times in a row, changing just one mash variable at a time:
- mash time
- mash temp
- pH monitoring (adjustment)
- mashout or not
- dough-in stir vigor
- drain / squeeze vigor
- crush

Out of curiosity, should I expect higher pre-boil eff from "traditional" mashing/sparging than from BIAB -- in general of course?

Thanks all!

 

[doug293cz]

I have never seen any convincing evidence that traditional mashing has an efficiency advantage over BAIB, or that BIAB has an advantage over traditional. There are multiple reports of BIAB mash (conversion + lautering) efficiencies of 85% - 90%. In the two experiments that I controlled as well as I could I achieved 84% & 89% mash efficiency.

Brew on

 

[Oginme]

I have never seen any convincing evidence that traditional mashing has an efficiency advantage over BAIB, or that BIAB has an advantage over traditional. There are multiple reports of BIAB mash (conversion + lautering) efficiencies of 85% - 90%. In the two experiments that I controlled as well as I could I achieved 84% & 89% mash efficiency.

Brew on

I agree with the lack of convincing evidence with regard to mash thickness and efficiency. IMHO, having a thick mash is a hold over from commercial brewing where you are trying to maximize (grain) volume of the mash and can effectively rinse the majority of the sugars via a fly sparge.

My mash/lauter efficiency consistently runs around 87% with full volume BIAB and around 90% when I do a BIAB with batch sparge . I crush very fine, squeeze quite a bit of the water out, and pay very close attention to my process consistency. My goal was not to achieve such a high efficiency, but to create a consistent process.

The times when I have dragged out my mash tun and done a more traditional mash with batch sparge, I achieve around 83% efficiency, mostly due to the fact that I back off on the grind to reduce probability of a stuck mash.

 

[wobdee]

I also brew 3 gal BIAB batches (mostly lagers) and with 5-6 lbs of grain I'm seeing steady 80-85% mash efficiencies with OG's in the 1.048- 1.060 range.

I think your main issue is the crush, I have my own mill and have it set to the width of a credit card. Maybe instead of using your local shop order from an online store like N Brewer and ask for a fine BIAB crush.

I'd also let your bag drain longer after you pull it. I let it hang for about 20 min while the kettle comes up to boil then set it in bucket for another half hour or so to collect more. You can squeeze if you like but I have found little or no difference in efficiency between the two. Gravity works if you give it time and imho I think squeezing pushes through unwanted crud into your kettle.