Mash Thickness and Efficiency

[SRJHops]

I have read conflicting things about mash thickness and efficiency. One source said that to improve efficiency I should mash thicker, while another source (see below) says a thinner mash increases the yield.

Yesterday I mashed a big Belgian Quad and got abysmal efficiency, around 55% (I usually get at least 70%). While I usually shoot for 1.75 qt/lb water for the mash, for that one I did 1.28 qt/lb because it was pushing the limits of my tun/system. Now I wish I would have increased the water to 1.75 qt/lb at least. I even mashed for two hours...

So why would folks suggest that a thicker mash could improve efficiency? I did see a post that said to mash thick so you can collect more sugar during the sparge. That did not make any sense to me, unless perhaps the person was fly sparging? I batch sparge. So I'm thinking if I can get most of the sugar from the first runnings, then top off with sparge water, that's a good way to go...

Here's the article saying a Thinner mash is better: Mashing, Thick or Thin? - Brewer's Friend

Would it have been a good idea to mash my Quad at 1.75 qt/lb or even 2 qt/lb?

 

[hotbeer]

Mash thickness if anything is more about what types of enzymatic reactions you'll have going on to produce various fermentable and unfermentable sugars.

Not really anything to do with efficiency, IMO.

There might be a little to how much starch converts, but I think the amounts have been shown to not be significant.

That being said, I do still mash at about 1.25 - 1.35 quarts to pound of grain. But that's because I'm still on a stove top and it lends itself better for my vessels and procedures.

 

[bracconiere]

So why would folks suggest that a thicker mash could improve efficiency?

i would, it allows me to sparge more? but then you have to balance boil off with extra sparging.....

 

[SRJHops]

i would, it allows me to sparge more? but then you have to balance boil off with extra sparging.....

I stop sparging when I hit my pre-boil volume, so not sure I am following...

 

[bracconiere]

I stop sparging when I hit my pre-boil volume, so not sure I am following...

but you would have to sparge more to get the same effec with a bigger grain bill is my point, so there would be more boil off involved....longer boil....

 

[hotbeer]

When you said "Efficiency" in your OP, I was taking that as mash efficiency or maybe brew house efficiency.

But I looked at the article you linked after I posted and saw that it talks about conversion efficiency which in my world at the moment, I don't think is the same as mash efficiency.

So which efficiency is the efficiency your OP ask about?

 

[odie]

conversion efficiency?

Mash efficiency?

Lauter efficiency?

brewhouse efficiency?

all are different.

getting the most sugar out of the mash requires more and more water....thus requires a longer boil off...thus requires more time and more energy (gas/elec).

I try to get as much sugar into the kettle as possible, but there is a point of diminishing returns.

 

[SRJHops]

but you would have to sparge more to get the same effec with a bigger grain bill is my point, so there would be more boil off involved....longer boil....

Are you saying I should have increased my pre-boil volume, then boiled longer to get to my pre-boil SG? That does make some sense to me... I stopped sparging when I hit my pre-boil target of 7 gallons, but maybe I left a bunch of sugar in the sparge grain...

So, one possibility, as someone mentioned above, is that mash thickness does not change the yield that much..... If that IS true, then next time I should collect more sparge water and plan to boil longer to get to my pre-boil volume and SG.

 

[day_trippr]

Are you saying I should have increased my pre-boil volume, then boiled longer to get to my pre-boil SG?

I do exactly that for an imperial chocolate stout that requires literally twice the pounds of malt than my more typical ipas/neipas/wheats/etc require...

Cheers!

 

[SRJHops]

conversion efficiency?

Mash efficiency?

Lauter efficiency?

brewhouse efficiency?

all are different.

getting the most sugar out of the mash requires more and more water....thus requires a longer boil off...thus requires more time and more energy (gas/elec).

I try to get as much sugar into the kettle as possible, but there is a point of diminishing returns.

I am talking mash efficiency... Bottom line is that I missed my pre-boil gravity by about 10 points. I didn't have any DME so I did drop in some more sugar to try to get there. I still ended up shy by 7 points in the end. Beer will likely still be good, but I want to figure out how to hit my pre-boil SG next time for this beer.

 

[SRJHops]

When you said "Efficiency" in your OP, I was taking that as mash efficiency or maybe brew house efficiency.

But I looked at the article you linked after I posted and saw that it talks about conversion efficiency which in my world at the moment, I don't think is the same as mash efficiency.

So which efficiency is the efficiency your OP ask about?

I assume mash efficiency is the same as conversion efficiency, correct? In any case, I am talking about not getting enough sugar extracted to hit my pre-boil SG target.

I feel like my overall process is pretty solid, though if I miss my pre-boil SG then all efficiencies suffer.

 

[SRJHops]

I do exactly that for an imperial chocolate stout that requires literally twice the pounds of malt than my more typical ipas/neipas/wheats/etc require...

Cheers!

So I likely left the sugar in the sparge grain, when I stopped sparging at my target of 7 gallons.

Do you have any thoughts on mash thickness?

 

[odie]

I am talking mash efficiency... Bottom line is that I missed my pre-boil gravity by about 10 points. I didn't have any DME so I did drop in some more sugar to try to get there. I still ended up shy by 7 points in the end. Beer will likely still be good, but I want to figure out how to hit my pre-boil SG next time for this beer.

well, just boil until you meet your target gravity. Your ending yield might be less than 5 gal of beer but you will be on target for gravity. Adjust your adjuncts as needed.

could either be you are not using enough grain to start with or your methods of getting the sugar out of the mash could use some refinement.

traditional 3V? BIAB?

My own process has gone thru many subtle, but effective refinements. We are all learning new ways to do it with every batch we make. Any everyone's equipment is a little different.

 

[mac_1103]

I stop sparging when I hit my pre-boil volume, so not sure I am following...

Thicker mash means more sparge water to get to the same target volume, but I'm the wrong guy to ask if it's necessarily better. I just do it that way because of the relative sizes of my cooler and kettle.

 

[odie]

I assume mash efficiency is the same as conversion efficiency, correct? In any case, I am talking about not getting enough sugar extracted to hit my pre-boil SG target.

I feel like my overall process is pretty solid, though if I miss my pre-boil SG then all efficiencies suffer.

conversion efficiency is how much potential sugars are converted from starch.

You should expect 100% with a good mash (temp and time).

The "trick" is getting that sugar out of the mash into the kettle. That's lauter efficiency. the more water the more efficiency. but volume goes up as SG goes down. thus the boil off gets longer and longer to return to target SG at beginning of the recipe boil period.

Mash efficiency I believe is a combination of both conversion and lauter.

 

[odie]

I think as the mash gets "thicker", the enzymes have to work harder to convert all starch to sugar, or it hits a "wall" and stops short.

I believe a thinner mash helps achieve full conversion, but then you will have a greater volume/lower SG wort to deal with (boil down).

Once you drain off the mash and start sparging...it's all the same "thickness" I would think

 

[SRJHops]

conversion efficiency is how much potential sugars are converted from starch.

You should expect 100% with a good mash (temp and time).

The "trick" is getting that sugar out of the mash into the kettle. That's lauter efficiency. the more water the more efficiency. but volume goes up as SG goes down. thus the boil off gets longer and longer to return to target SG at beginning of the recipe boil period.

Mash efficiency I believe is a combination of both conversion and lauter.

That all makes sense... I guess it's lauter efficiency, since it's both the mash and sparge.

I think next time I will increase the pre-boil target to 7.5 gallons and plan to boil for 2 hours. I do think I will increase the mash water to 1.75 qt/lb. I have a guess that fly sparging is more efficient, but since I batch sparge, maybe I should try to get more sugar extracted in the mash....

 

[SRJHops]

I think as the mash gets "thicker", the enzymes have to work harder to convert all starch to sugar, or it hits a "wall" and stops short.

I believe a thinner mash helps achieve full conversion, but then you will have a greater volume/lower SG wort to deal with (boil down).

Once you drain off the mash and start sparging...it's all the same "thickness" I would think

If it does hit a wall, then I'd think I want to mash thinner, so it all converts. Once I am sparging the conversion is over, and I am just rinsing the remaining sugar off the grains. Or that is how I understand it.

I would end up with higher SG mash water, then I would use more sparge water to rinse all the sugar. So I'm thinking instead of stopping the sparge at 7 gallons, as I usually do, I should collect at least 7.5 gallons and boil for two hours.

I rarely use this much grain, so my usual process did not work. I usually brew around 1.060 OG beers, but I was trying for 1.088.

 

[RM-MN]

Something that I think people are missing is where the sugar is at the end of the mash. Is it all freely mixed in the wort or is it held in the grain particles? If your grain is milled a bit more coarse, you can still get good conversion but with some of the sugar well inside the grain a simple sparge won't get them all out. For example, take a sugar cube. Give it a quick squirt of water and see how much sugar you collected. Some of the sugar will have dissolved but it will take a bit longer to dissolve all of it. If the sugar cube (I know, they don't come that way) was very big, you might not be able to collect all the sugar squirting water at it. That's why lauter efficiency is so critical.

 

[SRJHops]

Something that I think people are missing is where the sugar is at the end of the mash. Is it all freely mixed in the wort or is it held in the grain particles? If your grain is milled a bit more coarse, you can still get good conversion but with some of the sugar well inside the grain a simple sparge won't get them all out. For example, take a sugar cube. Give it a quick squirt of water and see how much sugar you collected. Some of the sugar will have dissolved but it will take a bit longer to dissolve all of it. If the sugar cube (I know, they don't come that way) was very big, you might not be able to collect all the sugar squirting water at it. That's why lauter efficiency is so critical.

Point well taken... I could be leaving some sugar on/in the grains after lautering the sparge grains. I do usually hit my targets, though. In this case what was different was the huge amount of grain. I have read that efficiency drops with the big beers... so I need to change my processes to compensate.

I personally just want to hit my SG targets..... I am not really chasing greater efficiency (I actually use kettle efficiency for my target). Thought I am not against greater efficiency!

With that said, does anyone have tips for batch sparging? I usually drop in the water at about 200 degrees and try to hit 170, though I've been told that if my ph is good I don't need to worry about tannins. I usually stir for a few minutes, then let it sit for 5 more minutes. Then I vorlauf and lauter. Whole sparge takes about 10 minutes. I have seen posts where people say the sparge should take much longer, but I have never understood why -- unless they are talking about fly sparging?

 

[odie]

If it does hit a wall, then I'd think I want to mash thinner, so it all converts. Once I am sparging the conversion is over, and I am just rinsing the remaining sugar off the grains. Or that is how I understand it.

conversion is just that. converting starch to sugar. it's still all in the grain bed. dissolved into the water, which is now called wort.

sparging/lautering is just the process of draining and rinsing the sugars out of the grain bed.

lauter and sparge terms are often used interchangeably but I think lauter is a "process" while sparge is just the rinsing part of the lauter "process".

 

[odie]

I think you could sparge a long time and still not get all the sugars out. The SG of what is running off just keeps dropping...while your kettle keep filling.

I've done some real big beers. RIS and stuff that is well over 1.100 OG and the "spent" grain was still running off at a nice 1.050 for a second beer.

 

[DuncB]

@SRJHops
Perhaps consider a reiterated mash.

 

[SRJHops]

@SRJHops
Perhaps consider a reiterated mash.

That's a great idea! Have you done it? I bet even 30 minutes would do the trick? Or do you think I should do another full hour... My brew day is getting pretty long!

 

[odie]

I often mash overnight or all day while at work. Extreme but I probably achieve 100% conversion. Maybe 99.99%

 

[hotbeer]

Some questions and points. Which I'll be glad for any to comment on since I'm not w whiz at this either.

1. Have you ever done a Iodine test during the mash? If not do them a few times. One right at the very start so you'll know what it looks like when little to no conversion has taken place.
2. Unconverted starch, AFAIK, shows just about as much SG change as starch converted fully to sugars. But I'm really unsure on this.
3. Conversion efficiency to me just means how much starch was effectively converted to sugars whether fermentable or not. Mash efficiency is more just the specific gravity you were able to get from your malts and other things mashed.
4. For most practical home brewing, it doesn't matter if your mash efficiency is 60% or 95%. What matters is that you know what your mash efficiency is and adjust the recipe amounts to match.
5. Many kits already seem to have recipes adjusted for a low mash efficiency. But recipes from individuals and elsewhere are likely up in the 75% - 80% range. But this is just from circumstantial observations when I've ever cared to notice and run the figures for.

 

[SRJHops]

Some questions and points. Which I'll be glad for any to comment on since I'm not w whiz at this either.

1. Have you ever done a Iodine test during the mash? If not do them a few times. One right at the very start so you'll know what it looks like when little to no conversion has taken place.
2. Unconverted starch, AFAIK, shows just about as much SG change as starch converted fully to sugars. But I'm really unsure on this.
3. Conversion efficiency to me just means how much starch was effectively converted to sugars whether fermentable or not. Mash efficiency is more just the specific gravity you were able to get from your malts and other things mashed.
4. For most practical home brewing, it doesn't matter if your mash efficiency is 60% or 95%. What matters is that you know what your mash efficiency is and adjust the recipe amounts to match.
5. Many kits already seem to have recipes adjusted for a low mash efficiency. But recipes from individuals and elsewhere are likely up in the 75% - 80% range. But this is just from circumstantial observations when I've ever cared to notice and run the figures for.

I have not done an iodine test. Will it tell me when conversion is complete? Sure would be better than guessing.

I actually use kettle efficiency for my recipes, and I have the software fairly dialed in to hit my numbers regularly. It was just this big beer that messed everything up...

 

[SRJHops]

I often mash overnight or all day while at work. Extreme but I probably achieve 100% conversion. Maybe 99.99%

I've done overnight too, but I worry about the temp getting too low. No worries for the beers I want dry, but could mess up the ones I want a bit sweeter/fuller.

I bet what we are really talking about is potential fermentable extract based on mash temp.

 

[odie]

temp controller, recirc pump and insulation. Mine stays 150 (or whatever I want) all day, all night.

 

[hotbeer]

I have not done an iodine test. Will it tell me when conversion is complete? Sure would be better than guessing.

This is the instructions I went by..

A simple method is the iodine test:

• Purchase some common liquid iodine, which is available at virtually any drug store. It typically is located with the first aid supplies, as it is sold as an antibiotic for use on cuts and scrapes.
• To run your test, draw a small sample of wort from the top of your mash tun. You only need a teaspoon size sample, and put it on a white plate so you can observe the color.
• Add a few drops of iodine to the wort. If there are unconverted starches in the wort it will quickly turn dark blue or black. This indicates that the mash is not complete.
• If the mash is complete it will be either clear or a slight shade of brown that is very close in color to the wort itself. This indicates that the mash starch conversion is complete and you can proceed with the sparge.

Using the iodine test can be a real time saver on brew day. With modern malts it is rare that you need a full 90 minute or even hour long mash. In many cases you can complete a mash in under 30 minutes.

The Iodine Test for Checking Mash Conversion.

Just be sure to do one soon after you get the malts mixed in so you know what what the difference is between the black that you get when the starch concentration is high and the just very dark blackish brown you might get in iodine that hasn't gotten diluted yet.

No need to do them every time. Just till you know you are getting what you should be. Or when things change in your process.

 

[day_trippr]

So I likely left the sugar in the sparge grain, when I stopped sparging at my target of 7 gallons.
Do you have any thoughts on mash thickness?

Not really. I run a 3v2p single tier brew rig with 20 gallon kettles doing 10.5 gallons to the kegs size batches so even with the 42 pounds of grain I use for the imperial stout I can hit the same 1.25 quarts per pound thickness that I use for all my brews that use half the malt. So my thoughts are on the back end - while my typical (65-70 point) batches use 14 gallons preboil I gather extra sparged gallons and boil harder for longer to hit the OG I'd like

Cheers!

 

[SRJHops]

This is the instructions I went by..


The Iodine Test for Checking Mash Conversion.

Just be sure to do one soon after you get the malts mixed in so you know what what the difference is between the black that you get when the starch concentration is high and the just very dark blackish brown you might get in iodine that hasn't gotten diluted yet.

No need to do them every time. Just till you know you are getting what you should be. Or when things change in your process.

That's pretty cool! I will give it a try. It actually sounds pretty simple. Even easier than checking the pH, with all the calibration and such...

 

[CascadesBrewer]

That's a great idea! Have you done it? I bet even 30 minutes would do the trick? Or do you think I should do another full hour... My brew day is getting pretty long!

What did your grain bill look like? I tend to not use a massive grain bill on "big" Belgian beers because of the amount of sugar added to the boil and since much of the higher ABV comes from the higher attenuation. I have had more challenges on grain bills for NEIPAs (and all-grain beers like Imperial Stouts and Barleywines).

 

[SRJHops]

What did your grain bill look like? I tend to not use a massive grain bill on "big" Belgian beers because of the amount of sugar added to the boil and since much of the higher ABV comes from the higher attenuation. I have had more challenges on grain bills for NEIPAs (and all-grain beers like Imperial Stouts and Barleywines).

I had about 19 pounds of grain and 2.5 pounds of sugar. Software is now showing OG 1.081, FG 1.014, for abv of 8.8%. I originally wanted OG of 1.088 to get to 9.5%. A bit on the low side for a quad, but within BJCP guidelines.

I have found that sugar sometimes throws off the software, so it could attenuate lower for sure. Maybe I will break 9% at least!

 

[dmtaylor]

I have read conflicting things about mash thickness and efficiency. One source said that to improve efficiency I should mash thicker, while another source (see below) says a thinner mash increases the yield.

Yesterday I mashed a big Belgian Quad and got abysmal efficiency, around 55% (I usually get at least 70%). While I usually shoot for 1.75 qt/lb water for the mash, for that one I did 1.28 qt/lb because it was pushing the limits of my tun/system. Now I wish I would have increased the water to 1.75 qt/lb at least. I even mashed for two hours...

So why would folks suggest that a thicker mash could improve efficiency? I did see a post that said to mash thick so you can collect more sugar during the sparge. That did not make any sense to me, unless perhaps the person was fly sparging? I batch sparge. So I'm thinking if I can get most of the sugar from the first runnings, then top off with sparge water, that's a good way to go...

Here's the article saying a Thinner mash is better: Mashing, Thick or Thin? - Brewer's Friend

Would it have been a good idea to mash my Quad at 1.75 qt/lb or even 2 qt/lb?

I did receive both of your other PMs. I thought about an answer, but was unable to reply for some reason.

I was the source of that other theory. The reason I said it is that I am a batch sparger too, BUT... I was double-sparging, dividing the mash volume and the two sparge volumes equally into not just two but THREE equal portions. Equalizing the volumes results in maximum batch sparge efficiency. So by mashing thick and then sparging not just once but twice, you extract the most you can. And, mashing thick ensures the volumes will actually fit in your mash tun! If your mash tun is enormous, then I suppose you wouldn't HAVE to mash it thicker. But wouldn't hurt.

Combine that also with planning to do not just a 60 to 90 minute boil, but how about a 2.5 to 3 hour boil. Collect way more sugar and boil off more water volume.

Make more sense now?

Otherwise, all processes being standard while aiming for a high gravity, your efficiency is going to suck a$S. You should expect an efficiency of 55% for standard process. But with the process I've mentioned above, you can still hit 80% or whatever.

Another alternative would be to partigyle. Make a really strong first runnings beer. Then make a second smaller beer with the second runnings. Your efficiency will be great then except that about 2/3 of the sugars end up in the first beer, and the second beer ends up with half the OG of the first one. The commercial English brewers love the partigyle method as I'm sure you've heard about. Fuller's is famous for producing all their beers this way using different blends. They might sparge twice if memory serves, making three volumes as I suggested above.

P.S. I have never done an iodine test. It would just be misleading more than anything else. Crush well, mash well, sparge well, ensure a mash pH around 5.3-5.6, and your conversion will be just fine.

 

[dmtaylor]

I stop sparging when I hit my pre-boil volume, so not sure I am following...

This is the problem.

Are you saying I should have increased my pre-boil volume, then boiled longer to get to my pre-boil SG? That does make some sense to me... I stopped sparging when I hit my pre-boil target of 7 gallons, but maybe I left a bunch of sugar in the sparge grain...

So, one possibility, as someone mentioned above, is that mash thickness does not change the yield that much..... If that IS true, then next time I should collect more sparge water and plan to boil longer to get to my pre-boil volume and SG.

Exactly!

 

[SRJHops]

I did receive both of your other PMs. I thought about an answer, but was unable to reply for some reason.

I was the source of that other theory. The reason I said it is that I am a batch sparger too, BUT... I was double-sparging, dividing the mash volume and the two sparge volumes equally into not just two but THREE equal portions. Equalizing the volumes results in maximum batch sparge efficiency. So by mashing thick and then sparging not just once but twice, you extract the most you can. And, mashing thick ensures the volumes will actually fit in your mash tun! If your mash tun is enormous, then I suppose you wouldn't HAVE to mash it thicker. But wouldn't hurt.

Combine that also with planning to do not just a 60 to 90 minute boil, but how about a 2.5 to 3 hour boil. Collect way more sugar and boil off more water volume.

Make more sense now?

Otherwise, all processes being standard while aiming for a high gravity, your efficiency is going to suck a$S. You should expect an efficiency of 55% for standard process. But with the process I've mentioned above, you can still hit 80% or whatever.

Another alternative would be to partigyle. Make a really strong first runnings beer. Then make a second smaller beer with the second runnings. Your efficiency will be great then except that about 2/3 of the sugars end up in the first beer, and the second beer ends up with half the OG of the first one. The commercial English brewers love the partigyle method as I'm sure you've heard about. Fuller's is famous for producing all their beers this way using different blends. They might sparge twice if memory serves, making three volumes as I suggested above.

P.S. I have never done an iodine test. It would just be misleading more than anything else. Crush well, mash well, sparge well, ensure a mash pH around 5.3-5.6, and your conversion will be just fine.

Thanks Man, this is good stuff!

If I understand.... For your process you are using twice as much sparge water as mash water, then collecting a larger pre-boil volume and boiling longer. It does provide good context for your thoughts about a thicker mash.

I'm still not sure if thick or thin is better, but it's clear I should be collecting more sparge water - at least for the big dark beers. I usually hit 70% efficiency for my big PALE beers like Tripels and Golden Strongs. So why did I get 55% for the Quad? Is there something about darker grains? Or did I mess up the process for THIS beer somehow?

Next time I brew a Quad I will consider a reiterated mash, and I do think I will try to mash a bit thinner. I will also collect more sparge water and plan to boil for at least 2 hours. I think I will also get some iodine and play around with that to see what I think.

Thanks to ALL who commented!

 

[dmtaylor]

I usually hit 70% efficiency for my big PALE beers like Tripels and Golden Strongs. So why did I get 55% for the Quad? Is there something about darker grains? Or did I mess up the process for THIS beer somehow?

It might be a mash pH thing. Dark roasted grains are inherently acidic. If a pale beer turns out fine but a dark beer has lower efficiency, consider whether your mash pH might have fallen down to 4.9-5.1 or something like that, far from the ideal of 5.3 or more.

 

[mac_1103]

Dark roasted grains are inherently acidic. If a pale beer turns out fine but a dark beer has lower efficiency, consider whether your mash pH might have fallen down to 4.9-5.1 or something like that, far from the ideal of 5.3 or more.

Yeah, so I'm getting ready to do a kitchen sink stout with all of my leftover specialty grains. If the brewer's friend calculator is to be believed, the black patent and especially the chocolate wheat are going to make my pH way too low (4.2 instead of 5.3). I want them mostly for color anyway, so I guess I could just steep them separately. But when should I add that tea to the wort to avoid screwing things up?

 

[dmtaylor]

Yeah, so I'm getting ready to do a kitchen sink stout with all of my leftover specialty grains. If the brewer's friend calculator is to be believed, the black patent and especially the chocolate wheat are going to make my pH way too low (4.2 instead of 5.3). I want them mostly for color anyway, so I guess I could just steep them separately. But when should I add that tea to the wort to avoid screwing things up?

Add it in the last 5 minutes of the mash, along with a nice teaspoon of baking soda or pickling lime to offset the pH effects.