Mash thickness and efficiency

[rtstrider]

Hello all! I've recently moved from BIAB to a mash tun cooler setup. This is a backwards step as seen by some but a buddy was getting rid of their setup for a price I couldn't refuse. Figured I'd try it for giggles. Anywho I've been getting consistently around 60% efficiency. I do fly sparge for an hour and vorlauf. The constant is the mash thickness has been in the 1.25 qt per lb of grain range. This is being used due to John Palmer How to Brew. I've read a few forums (not this one) that state increasing the qt to lb ratio can/will yield better efficiency. Has anyone personally played around with this and if so did this help?

 

[Sammy86]

Personally, I'm a 1.5/LB guy...in my cooler mash tun I consistently get 75-80% efficiency...however the one or two times I did go lower I didn't see that significant of a drop maybe 1 or 2 points.

What have the grain bills?

 

[Dustin_J]

Braukaiser has done a handful of tests on various mash parameters examining both efficiency and fermentability: http://braukaiser.com/wiki/index.ph...single_infusion_mashing#mash_thickness_series

Briefly, he got better efficiency from thinner (~2.4 qts/lb) vs thicker (~1.2 qts/lb) mashes with no substantial differences in fermentability. Note that he also cites brewing science textbooks (Briggs, Narziss) that discuss similar findings.

 

[bucketnative]

I'd be more suspicious of the crush or sparge technique before I chased mash thickness.

 

[RM-MN]

Fly sparging can be a source of poor efficiency if not done well but crush quality is probably the most likely cause. One quick way to determine which causes your poorer efficiency is to forego the fly sparge and replace it with a double batch sparge. Make sure to stir well for each batch sparge.

 

[DVCNick]

I'd be more suspicious of the crush or sparge technique before I chased mash thickness.

This...

I've done 1.25, 1.375, 1.5, never noticed a difference. But when I went to batch sparging, with complete drains for first and second step, my efficiency went up. It makes sense to me like this: When I drain all the way (minus the deadspace in the bottom, which is what it is in your system) All the converted sugars that are dissolved in the water go into your kettle.

With fly sparging, you are just diluting them most of the time, and if you don't get your volume exactly right and leave any drainable liquid in the mashtun, you have left some sugar behind that was there for the taking.

My efficiency went from low 70's to mid-upper 70's when I made this change... ymmv of course.
I could probably go after even more with a finer crush, but I had a stuck sparge once (not due to crush) and would very much like to avoid a repeat of that experience.

 

[rtstrider]

I'd be more suspicious of the crush or sparge technique before I chased mash thickness.

The crush is good. I've used the same LHBS for the previous BIAB setup. In that setup I was getting 75-80% efficiency. Mind you the mash was THIN! So that's why I'm curious if that may be the culprit. Next brew is supposed to be a Space Dust clone so I've adjusted for 60% efficiency. Recipe after that will be a simple single malt/single hop, helles style, lager. Figure I could play with a thinner mash on that since it's simple and will basically be a yeast building brew anywho. I read on a forum where someone said you can go up to 3 qts water per lb of grain without any negative affects.

Edit: Do you happen to stir the mash every so often? If so does that make a difference?

 

[bucketnative]

The crush is good. I've used the same LHBS for the previous BIAB setup. In that setup I was getting 75-80% efficiency. Mind you the mash was THIN! So that's why I'm curious if that may be the culprit. Next brew is supposed to be a Space Dust clone so I've adjusted for 60% efficiency. Recipe after that will be a simple single malt/single hop, helles style, lager. Figure I could play with a thinner mash on that since it's simple and will basically be a yeast building brew anywho. I read on a forum where someone said you can go up to 3 qts water per lb of grain without any negative affects.

Edit: Do you happen to stir the mash every so often? If so does that make a difference?

I don't stir the mash. For a 10 lb grain bill, my cooler at max volume (5 gal) will yield about 1.33 qt/lb. I leave it be for 60 to 75 minutes prior to draining the mashtun. Then I do a single batch sparge (3.5 gal) with vigorous stirring at the start. Typically right around 80 % efficiency for me. I do 4 gal (fermenter volume) batches.

If you're using the same crush size for your mashtun as you do with BIAB, then I might suspect it is on the finer side. It is possible that your fly sparge is channeling and not completely rinsing the sugars from your grains. I would try a batch sparge before any other variables.

 

[brewbama]

I use 1.75/1 and get 87% +/- mash efficiency and 72% +/- brew house efficiency.

 

[rtstrider]

I don't stir the mash. For a 10 lb grain bill, my cooler at max volume (5 gal) will yield about 1.33 qt/lb. I leave it be for 60 to 75 minutes prior to draining the mashtun. Then I do a single batch sparge (3.5 gal) with vigorous stirring at the start. Typically right around 80 % efficiency for me. I do 4 gal (fermenter volume) batches.

If you're using the same crush size for your mashtun as you do with BIAB, then I might suspect it is on the finer side. It is possible that your fly sparge is channeling and not completely rinsing the sugars from your grains. I would try a batch sparge before any other variables.

That actually makes a ton of sense in regards to the fly sparge. It is definitely channeling so I may toy with putting a layer of foil with holes over the grain bed next batch and see what happens

 

[blizz81]

I've been using 1.25 + volume under my false bottom (0.875gal) for a while. Used to get high 70s re: brewhouse efficiency for a few years, but had strayed from that number recently. Made some changes, got back to 78% three brews ago, had some recirc channeling issues in the next brew and was at 70%, and last brew was big (24lb grain for a 5.5gal batch), expected a hit on that since my batch sparge volume was low compared to my first runnings (but was still at 10gal preboil) - got 73%. There's a variety of factors here.

For me, I brew mostly higher-gravity beers, so if I went any higher than 1.25 on mash thickness, I imagine I'd have to lengthen my boils (even longer in a lot of cases, most are over 60 mins as is) or take an efficiency hit having less volume for sparging. I have had a couple cases where due to issues in mashing, I've used some or all of my sparge volume in the mash instead, and saw lower brewhouse efficiency on those batches.

 

[rlonardo]

Look into trying out the batch sparge method. It will definitely save you time and will probably bump up your efficiency. I dump my full sparge volume in after I drain the mash, give it a stir and let it rest for 10 minutes, then drain again.

I also don't think it hurts to stir the mash occasionally. I usually stir about every 20 minutes.

 

[RM-MN]

Look into trying out the batch sparge method. It will definitely save you time and will probably bump up your efficiency. I dump my full sparge volume in after I drain the mash, give it a stir and let it rest for 10 minutes, then drain again.

I also don't think it hurts to stir the mash occasionally. I usually stir about every 20 minutes.

Your efficiency will go up a bit and the time will likely also go down if you dump in half the sparge, stir, then drain immediately. Repeat that and you are done. The sugars are not bound to the grain and it doesn't take 10 minutes to break them loose. Stir well.

 

[DatsyukianDeke]

Interesting. I've been doing a single batch sparge that I let sit for 10-15 minutes and I get 65-67% pretty consistently. Next brew I'll split that into two batches with the extra time and see what I get.

 

[doug293cz]

The crush is good. I've used the same LHBS for the previous BIAB setup. In that setup I was getting 75-80% efficiency. Mind you the mash was THIN! So that's why I'm curious if that may be the culprit. Next brew is supposed to be a Space Dust clone so I've adjusted for 60% efficiency. Recipe after that will be a simple single malt/single hop, helles style, lager. Figure I could play with a thinner mash on that since it's simple and will basically be a yeast building brew anywho. I read on a forum where someone said you can go up to 3 qts water per lb of grain without any negative affects.

Edit: Do you happen to stir the mash every so often? If so does that make a difference?

You shouldn't get lower efficiency with a fly sparge (or batch sparge) vs. BIAB. The thicker mash may slow down the conversion rate, which should be correctable with a longer mash. Stirring may also help speed up conversion. To make sure your conversion is complete, you should measure the SG of the wort in the mash, and compare with the table here.

I suspect that much of your issue is with poor lauter efficiency of your fly sparge. I second the recommendation to try batch sparging. If you can't beat a batch sparge with your fly sparge, you are wasting your time with a fly sparge. For a single batch sparge, use 60% of your total brewing water for strike, and 40% for sparge. If you are going to do a double batch sparge, then the volumes should be 50%, 25%, & 25%. These volume recommendations will give you near optimal lauter efficiency results, without having to do any complex calculations.

That actually makes a ton of sense in regards to the fly sparge. It is definitely channeling so I may toy with putting a layer of foil with holes over the grain bed next batch and see what happens

Channeling is more likely due to the bottom of your MLT than the top. If you have a braid type pick-up, forget fly sparging, and do batch sparge. For a good fly sparge you need a false bottom that allows unrestricted wort flow under the grain bed. If you don't have this, you are likely to have channeling issues, no mater how you distribute the sparge water on top of the mash. If you fly sparge with 1" - 2" of water on top of the grain bed, it does not mater how you add the sparge water.

Brew on

 

[rtstrider]

You shouldn't get lower efficiency with a fly sparge (or batch sparge) vs. BIAB. The thicker mash may slow down the conversion rate, which should be correctable with a longer mash. Stirring may also help speed up conversion. To make sure your conversion is complete, you should measure the SG of the wort in the mash, and compare with the table here.

I suspect that much of your issue is with poor lauter efficiency of your fly sparge. I second the recommendation to try batch sparging. If you can't beat a batch sparge with your fly sparge, you are wasting your time with a fly sparge. For a single batch sparge, use 60% of your total brewing water for strike, and 40% for sparge. If you are going to do a double batch sparge, then the volumes should be 50%, 25%, & 25%. These volume recommendations will give you near optimal lauter efficiency results, without having to do any complex calculations.


Channeling is more likely due to the bottom of your MLT than the top. If you have a braid type pick-up, forget fly sparging, and do batch sparge. For a good fly sparge you need a false bottom that allows unrestricted wort flow under the grain bed. If you don't have this, you are likely to have channeling issues, no mater how you distribute the sparge water on top of the mash. If you fly sparge with 1" - 2" of water on top of the grain bed, it does not mater how you add the sparge water.

Brew on

I guess I'm misunderstanding channeling then. It does create a small dimple where the sparge water comes in. I do have a false bottom. The setup I have is an old Northern Brewer cooler mash tun/hlt with a false bottom. One thing I haven't been doing is slowly adding the grains and stirring as they're being added. I add them all at once and stir after the fact. Going to have one of the kiddos help with that next time so I can slowly add the grains and stir. That's what I did with BIAB at the very least.

 

[kevin58]

For a single batch sparge, use 60% of your total brewing water for strike, and 40% for sparge.

That's a broad generalization. It will get you in the ballpark but grain absorption and mash tun deadspace might throw off the results a small amount. The purpose of that is really to have equal amounts from each sparge going into the boil kettle. I learned batch sparging from Denny Conn who, at the time was no doubt the loudest proponent if not one of the first advocators of this sparge method. If you want to get into the weeds and calculate more accurate volumes I copied this from his website:
-
The main concept we’re going to be working with is that for the best efficiency, the runoff volumes from your mash and batch sparge should be equal. In order to do that, it’s sometimes necessary to infuse your mash with extra water before the first runoff. Here’s how it works...

R1=initial runoff volume which = mash water volume - water absorbed by grain
(assumed to be .1 gal./lb. for this example since that’s the way my system works...use your own figure)


S= batch sparge water volume
V= total boil volume (amount in needed in kettle for boil)
I=volume of infusions for a step mash


R1+I+S(1)+S(2)+S(etc.) must equal V
AND
R1+I=.5V


Let’s see how this works in a brewing session. Assume a recipe with 10 lb. of grain, and that you need to collect 7 gal. of pre boil wort. A mash ratio of 1.25 qt./lb. would require 12.5 qt. or 3.125 gal. of strike water. Based on an absorption of .1 gal./lb., the mash would absorb 1 gal. of water so we’d get 2.125 gal. of water from the mash. Since we want to collect 3.5 gal. (or 50% of the boil volume), after the mash is complete we’d add 1.375 gal. (5.5 qt.) of water to mash tun before the first runoff. Stir the additional water in, let it sit for a few minutes, then vorlauf until clear and start your runoff. After the runoff, we add 3.5 gal. of batch sparge water. Stir it in well, then vorlauf and runoff as before. These two runoffs will give us our pre boil volume of 7 gal. of sweet wort.
-
For what its worth, I often just added the extra 1.375 gallons (or whatever it calculated out to for a particular recipe) to the strike water rather than when the mash was complete. It gave me a thinner mash but I never noticed any differences when I compared the two methods.

 

[DVCNick]

At least with my process and the order of operations of my calculations, adding more strike water would throw off my mash water chemistry and pH calcs since they are done assuming the "correct" amount of strike water.

I used to try to add the "correct" amount of water after the mash to get two equal drain steps, but recently I've become more lazy about that... I just throw a couple gallons in, drain it, and see where I'm at. I then add exactly the difference between were I am and where I want to be, and drain again and that gets me to the desired preboil volume.

What is the benefit of draining exactly the same amount in two steps?

 

[doug293cz]

That's a broad generalization. It will get you in the ballpark but grain absorption and mash tun deadspace might throw off the results a small amount. The purpose of that is really to have equal amounts from each sparge going into the boil kettle. I learned batch sparging from Denny Conn who, at the time was no doubt the loudest proponent if not one of the first advocators of this sparge method. If you want to get into the weeds and calculate more accurate volumes I copied this from his website:
-
The main concept we’re going to be working with is that for the best efficiency, the runoff volumes from your mash and batch sparge should be equal. In order to do that, it’s sometimes necessary to infuse your mash with extra water before the first runoff. Here’s how it works...

R1=initial runoff volume which = mash water volume - water absorbed by grain
(assumed to be .1 gal./lb. for this example since that’s the way my system works...use your own figure)


S= batch sparge water volume
V= total boil volume (amount in needed in kettle for boil)
I=volume of infusions for a step mash


R1+I+S(1)+S(2)+S(etc.) must equal V
AND
R1+I=.5V


Let’s see how this works in a brewing session. Assume a recipe with 10 lb. of grain, and that you need to collect 7 gal. of pre boil wort. A mash ratio of 1.25 qt./lb. would require 12.5 qt. or 3.125 gal. of strike water. Based on an absorption of .1 gal./lb., the mash would absorb 1 gal. of water so we’d get 2.125 gal. of water from the mash. Since we want to collect 3.5 gal. (or 50% of the boil volume), after the mash is complete we’d add 1.375 gal. (5.5 qt.) of water to mash tun before the first runoff. Stir the additional water in, let it sit for a few minutes, then vorlauf until clear and start your runoff. After the runoff, we add 3.5 gal. of batch sparge water. Stir it in well, then vorlauf and runoff as before. These two runoffs will give us our pre boil volume of 7 gal. of sweet wort.
-
For what its worth, I often just added the extra 1.375 gallons (or whatever it calculated out to for a particular recipe) to the strike water rather than when the mash was complete. It gave me a thinner mash but I never noticed any differences when I compared the two methods.

Yes, equal run-off volumes gives the highest possible lauter efficiency. But, the volume ratio range of near optimal efficiency is quite broad. The chart below is from Braukaiser:

There is less than 1% lauter efficiency difference between 50/50 run-off ratio and 60/40 or 40/60 (initial/sparge). My recommendation of 60% strike and 40% sparge will end up closer to 50/50 after grain absorption. In practice efficiency calculations have an uncertainty range of 3% - 4%, so a 1% difference is realistically undetectable.

If you want to be precise, then do the calculations. If you want the easy way, use a 60/40 ratio (or 50/25/25 for double sparge). No one will be able to tell the difference. If your undrainable MLT volume is enough to shift the ratio so that the lauter efficiency is significantly affected, then you need a new MLT drain arrangement. That much undrainable MLT volume will significantly reduce the lauter efficiency regardless of the run-off ratio.

And rather than mash at some "magic" water to grain ratio, and then add more water just prior to run-off, just mash with more water. Thinner mashes convert faster anyway.

At least with my process and the order of operations of my calculations, adding more strike water would throw off my mash water chemistry and pH calcs since they are done assuming the "correct" amount of strike water.

I used to try to add the "correct" amount of water after the mash to get two equal drain steps, but recently I've become more lazy about that... I just throw a couple gallons in, drain it, and see where I'm at. I then add exactly the difference between were I am and where I want to be, and drain again and that gets me to the desired preboil volume.

What is the benefit of draining exactly the same amount in two steps?

It's easy enough to do the water calculations for the larger strike volume.

Your method is actually a double batch sparge, and will have a small improvement in lauter efficiency vs. a double batch sparge, even tho you are not close to equal run-off volumes for each step.

Brew on

 

[rtstrider]

I wanted to give a heads up. I brewed a single malt Pilsner yesterday and hit 70% efficiency on the dot! The two changes I made were....I poured the grains in slowly while my stepson stirred and mashed with a 1.8 qt per lb ratio. I did vorlauf and fly sparge as I normally do. So that's a nice change! The one thing I noticed is it was a bit more difficult to get the grain bed to "set" when vorlaufing/sparging. The fix for vourlauf was to pull 1.5 gallons wort at a time instead of the two quarts I normally pull. Anywho went from 59%-60% to 70% on the nose. That's what I'm used to so hey I'll take it!