Mash Thickness and Efficiency

[doug293cz]

Aren't most Mash done with conversion in ~30 minutes, at least with today's highly modified grains?
Given that, and it seems true when I test for conversion midway through the mash, if you mash-out at say 60 minutes, you aren't really stopping the conversion are you? Because the modern grains are done long before then.
Don't the equations tend to be aiming for as close to full conversion as is possible with a given grain bill. And in that case they set the mash time based on that time requirement.
Or are they just shotgunning it and saying 60 minutes?

Time to complete conversion in the mash is highly dependent on the crush coarseness or fineness. Fine crushes can achieve complete conversion in 20-30 minutes, but coarse crushes (most supplier crushes are coarse) may take significantly longer than an hour to complete conversion.

Conversion is a two step process. Before the enzymes can act on the starch chains, the starch must be gelatinized (swollen by the absorption of water - this is what happens when you cook rice or oatmeal.) Once (at least the surface of) a starch grain is gelatinized, then the enzymes can come in contact with the starch molecules, in the presence of water to cleave chain bonds. Each bond that is cleaved requires one water molecule to complete the reaction. You have to cleave lots of bonds to convert starch to fermentable sugar.

The gelatinization step is the rate controlling step. Actual hydrolysis (the bond cleaving) happens quite quickly. Gelatinization starts at the surface of grain grits, and proceeds towards the center. The larger the grit, the longer it takes to completely gelatinize. And, you cannot have complete conversion without complete gelatinization.

There are many threads on HBT asking "why is my efficiency so low?" When enough data is available for diagnosis, it often turns out that conversion efficiency is much lower than 100%, and this is almost always because the mash was too short for the coarseness of the grain crush. I have seen one case where the mash pH was way out of whack (much less than 5.0) that had almost no conversion, but that is a rare case.

Conversion can be monitored quantitatively by measuring the SG of the wort during the mash. For accurate results the wort must be well homogenized (aggressive stirring or recirculation) before taking SG samples. Take a sample every 15 minutes (you can start after 30 or 45 minutes if you wish), and when the SG doesn't increase between samples, the mash is done. A refractometer is very handy for this kind of sampling. Turns out the maximum SG of the mash wort is only a function of the weighted average grain potential and the mash thickness (water to grain ratio.) Since most typical mashes have weighted potentials of about 37 points/lb (or 80% max extract) it's possible to create a table that shows max mash SG vs. mash thickness (in qt/lb.) When you hit max SG, your mash is done. Here is such a table:

Specific Gravity at 100% conversion for various mash thicknesses​
​	​	​
Mash Thickness (qt/lb)​	Max °Plato​	Max SG​
0.75​	33.0​	1.1436​
0.80​	31.6​	1.1367​
0.85​	30.3​	1.1304​
0.90​	29.1​	1.1247​
0.95​	28.0​	1.1195​
1.00​	26.9​	1.1147​
1.05​	26.0​	1.1103​
1.10​	25.1​	1.1062​
1.15​	24.3​	1.1023​
1.20​	23.5​	1.0988​
1.25​	22.8​	1.0955​
1.30​	22.1​	1.0924​
1.35​	21.5​	1.0895​
1.40​	20.8​	1.0868​
1.45​	20.3​	1.0842​
1.50​	19.7​	1.0818​
1.55​	19.2​	1.0795​
1.60​	18.7​	1.0774​
1.65​	18.3​	1.0753​
1.70​	17.8​	1.0734​
1.75​	17.4​	1.0715​
1.80​	17.0​	1.0698​
1.85​	16.6​	1.0681​
1.90​	16.3​	1.0665​
1.95​	15.9​	1.0650​
2.00​	15.6​	1.0636​
2.05​	15.2​	1.0622​
2.10​	14.9​	1.0609​
2.15​	14.6​	1.0596​
2.20​	14.4​	1.0584​
2.25​	14.1​	1.0572​
2.30​	13.8​	1.0561​
2.35​	13.6​	1.0550​
2.40​	13.3​	1.0539​
2.45​	13.1​	1.0529​
2.50​	12.9​	1.0520​
2.55​	12.6​	1.0511​
2.60​	12.4​	1.0502​
2.65​	12.2​	1.0493​
2.70​	12.0​	1.0484​
2.75​	11.8​	1.0476​
2.80​	11.6​	1.0469​
2.85​	11.5​	1.0461​
2.90​	11.3​	1.0454​
2.95​	11.1​	1.0447​
3.00​	10.9​	1.0440​
3.05​	10.8​	1.0433​
3.10​	10.6​	1.0427​
3.15​	10.5​	1.0420​
3.20​	10.3​	1.0414​
3.25​	10.2​	1.0408​
3.30​	10.1​	1.0402​
3.35​	9.9​	1.0397​
3.40​	9.8​	1.0391​
3.45​	9.7​	1.0386​
3.50​	9.5​	1.0381​
3.55​	9.4​	1.0376​
3.60​	9.3​	1.0371​
3.65​	9.2​	1.0366​
3.70​	9.1​	1.0362​
3.75​	9.0​	1.0357​
3.80​	8.8​	1.0353​
3.85​	8.7​	1.0348​
3.90​	8.6​	1.0344​
3.95​	8.5​	1.0340​
4.00​	8.4​	1.0336​

Brew on

 

[bracconiere]

Maybe what @bracconiere was trying to ask was about a point after which it's silly to keep sparging just to get a tiny additional amount of sugar into the kettle. Not a theoretical limit exactly... but what is a silliness limit?

Brewing in a more intuitive way with less regard for "hitting numbers," I have sometimes continued sparging until the liquid going into the kettle has no apparent sweetness -- i.e., before it becomes astringent tasting.

damn, you reminded me of what i was trying remember! sparge until the run off hits ~1.010....if you're doing a BIG beer you'll probably hit it after you thought you would, thus end up with more wort in the kettle.....

 

[doug293cz]

Perhaps it's time to plug my Mash and Lauter Simulator spreadsheet again. You can use this sheet to make predictions of your efficiency based on recipe and process, or even (using "Goal Seek") to tell you how much grain you need to hit a given OG! To use the spreadsheet, you need to download a copy as either an Excel or LibreOffice format sheet, and work with the local copy.

Here's what the input section looks like:

You can select either imperial or metric units using a drop down in the "Units" input box. Grain bill potential can be entered as either points per pound (often called ppg), or in percent extract. Percent extract takes precedence if both are entered. You can specify up to 3 sparge steps, and the sheet will determine the strike and sparge volumes for equal run-off volumes. It will reduce sparge volumes if needed to maintain your minimum mash water to grain ratio (maximum mash thickness.) You can override the sheet selected strike and sparge volumes by entering values in the blue boxes shown here:

To determine how much grain you need to hit a given OG based on your process profile data that you input, you need to use the "Goal Seek" functionality of your spreadsheet. The LibreOffice Goal Seek drop down menu looks like this (Excel is similar but the terminology is slightly different):

For "Formula cell:" enter "K59" (it can be a little more accurate than K55, but K55 works too.) In "Target value:" enter your target OG. For "Variable cell:" enter "B5" (Total Grain Weight). When you have made all three entries, click the "OK" button.

Brew on

 

[VikeMan]

Conversion can be monitored quantitatively by measuring the SG of the wort during the mash. For accurate results the wort must be well homogenized (aggressive stirring or recirculation) before taking SG samples. Take a sample every 15 minutes (you can start after 30 or 45 minutes if you wish), and when the SG doesn't increase between samples, the mash is done.

When the SG stabilizes, conversion is complete. But I'll add that fermentability, OTOH, may still be increasing. This is the reason I rarely do iodine tests or SG monitoring during the mash to determine when to stop. I use mash length as a knob to target fermentability.

 

[bracconiere]

that spreadsheet is private only?

 

[doug293cz]

When the SG stabilizes, conversion is complete. But I'll add that fermentability, OTOH, may still be increasing. This is the reason I rarely do iodine tests or SG monitoring during the mash to determine when to stop. I use mash length as a knob to target fermentability.

If you determine SG stability by samples 15 min apart, then conversion was complete by the second to last sample. You then gave it 15 more minutes for hydrolysis to continue increasing fermentability. I would say you are pretty much done after that extra 15 minutes.

On the other hand, if you are working from a max obtainable mash SG table, and stop the mash when you think you are "close enough" to 100% conversion, then you may still have some fermentability to gain by waiting longer.

Brew on

 

[doug293cz]

that spreadsheet is private only?

You should be able to download a copy ("File -> Download -> {format option}".) Giving random people the ability to edit the on-line version would lead to chaos.

Brew on

 

[VikeMan]

If you determine SG stability by samples 15 min apart, then conversion was complete by the second to last sample. You then gave it 15 more minutes for hydrolysis to continue increasing fermentability. I would say you are pretty much done after that extra 15 minutes.

I hear you. But I'll point out that Greg Doss' (Wyeast) fermentability study saw an increase in fermentability at each step from 45 to 60 to 75 minutes. And Kai Troester saw increases from 15 to 30 to 45 to 60 to 90 to 280 minutes. Of course these observations were under their specific experimental conditions, but they are consisent in broad strokes with my own experience. Also, it's unfortunate that neither (afair) determined when conversion was complete. But in my own batches, I've done mashes ranging from as short as 30 minutes (with full conversion) to as long as 90 under essentially the same conditions, and for the most part I do see the attenuability differences I'm expecting with various mash times (per BrewCipher's predictions).

I'm of the opinion that amylase enzymes are generally laboring away for longer than they are usually given credit (in BYO Articles, etc.). And I believe it's because of the tendency to denature in a half-life-like fashion. It's like walking the proverbial half the distance to a wall, then half again, ad infinitum. (The difference of course being that mashes have a limited substrate.)

 

[dmtaylor]

When you say that's the process you use, do you really use a mash thickness of 1.0 qt/lb? That's really getting low...

Could I ask your opinion about the reiterated mash? Maybe it's not really necessary if I do the 50-25-25 with the double batch sparge?

Yes, I have gone down as low as 0.9 qt/lb. It is thick but doable.

Reiterated mash seems like a good process. I have not tried it myself but maybe someday.

 

[InspectorJon]

I did some research and came to the conclusion that 1 qt/lb of grain was kind of the limit with diminishing returns if one goes thicker. There is a thread here that discusses this and a big stout I did pushing my system to its limits if you are interested.

 

[SRJHops]

Thanks again to all for this great discussion!

So, one thing I've realized is that I got too comfortable with my strike/sparge water process (and was also doing some things wrong). Instead, I should be using a calculator every time. Is there any reason not to trust this calculator? Should I be using even more water? Or just go with the double sparge as recommended in the discussion above?

This calculator gives me about equal runnings using 1.33 mash thickness. Total water is 10.4 gallons.

Mash and Sparge Infusion Water Calculator | Brewgr

Mash and sparge water temperature infusion calculator for homebrew.

brewgr.com

Grain Weight
20 lb
Grain Temp
70°F
Target Mash Temp
151°F
Mash Thickness
1.33qt/lb
Total Boil Time
90min.
Wort Into Fermenter
5gals
Equipment Profile
Grain Absorption
0.15 gals/lb
Sparge Grain Absorption
0.01 gals/lb
HLT-MT Heat Loss
0°F
Mash Tun Loss
0.25 gals
Brew Kettle Trub Loss
0.5 gals
Boil Loss
1 gals/hour
Wort Shrinkage
0.2 gals
Calculated Totals
Total Water Needed
10.40
gals
Mash Tun Capacity
8.25 gals
Mash/Strike Volume
6.90 gals
HLT Temperature
162.74 °F
Strike Temperature
162.74 °F
1st Runnings
3.90
gals
Sparge Volume
3.50 gals
Total Runoff
7.2 gals

 

[dmtaylor]

Still should expect no more than about 65% efficiency with that process. Probably 60%. Still would benefit greatly from a much bigger sparge and much longer boil.

 

[SRJHops]

When the SG stabilizes, conversion is complete. But I'll add that fermentability, OTOH, may still be increasing. This is the reason I rarely do iodine tests or SG monitoring during the mash to determine when to stop. I use mash length as a knob to target fermentability.

Can you help me understand that point about fermentability? If we're at 100% conversion?

Last night I was reading Conn & Beechum's "Homebrew All-Stars." Fred Bonjour, a homebrewer who specializes in big beers, said this: "I also recommend a thin mash, greater or equal to 2 quarters per pound of malt, to promote greater fermentability."

 

[bracconiere]

at a certain point i'd imagine, it'd be best/cheaper/easier to 'supplement' with DME or LME? but i don't many big beers just 1.060...

edit: lol, consider it a partial extract batch instead a partial mash!

 

[SRJHops]

Still should expect no more than about 65% efficiency with that process. Probably 60%. Still would benefit greatly from a much bigger sparge and much longer boil.

So you are saying not to trust that calculator, at least for BIG beers?

 

[VikeMan]

Can you help me understand that point about fermentability? If we're at 100% conversion?

100% conversion just means that all of the starches have been converted to fermentable sugars and unfermentable dextrins.

The longer the mash goes (up to some point), the more dextrins are broken down into fermentable sugars. Results from the wort being more fermentable include lower final gravity and higher ABV, because of higher attenuation. Sometimes this is a good/desirable thing, sometimes not, depending on the beer style and the brewer's goals. There are also other things that affect fermentability. Here are what I'd call the big four, in no particular order:

- Grain Bill (and non-grain adjunct) makeup
- Yeast Strain
- Mash Temperature
- Mash Length

All of the above are "control knobs" that can be used to shape attenuation.

 

[SRJHops]

100% conversion just means that all of the starches have been converted to fermentable sugars and unfermentable dextrins.

The longer the mash goes (up to some point), the more dextrins are broken down into fermentable sugars. Results from the wort being more fermentable include lower final gravity and higher ABV, because of higher attenuation. Sometimes this is a good/desirable thing, sometimes not, depending on the beer style and the brewer's goals. There are also other things that affect fermentability. Here are what I'd call the big four, in no particular order:

- Grain Bill (and non-grain adjunct) makeup
- Yeast Strain
- Mash Temperature
- Mash Length

All of the above are "control knobs" that can be used to shape attenuation.

Thanks... You didn't list mash thickness, which the guy seems to think can also increase/decrease fermentability...

 

[VikeMan]

Thanks... You didn't list mash thickness, which the guy seems to think can also increase/decrease fermentability...

The guy might be wrong. Kai Troester found no difference. And I can't say that I've ever seen it listed as a fermentability driver in textbooks/white papers.

 

[SRJHops]

The guy might be wrong. Kai Troester found no difference. And I can't say that I've ever seen it listed as a fermentability driver in textbooks/white papers.

Fair enough... You can see why I made the original post, because I keep seeing people saying a thinner mash is better...

With that said, I am going to see for myself and focus more on getting the equal runnings and doing a double sparge.

I am still not 100% sure on whether to use that calculator - or a different one - to calculate my water amounts. Maybe I will see if the one posted above results in different volumes.

 

[dmtaylor]

So you are saying not to trust that calculator, at least for BIG beers?

Not exactly. Bigger beers will simply tend to have lower efficiency if you stick close to standard single batch sparge process. You have a choice. You can choose to stay close to standard process per your calculator or similar and suffer the lower efficiency, OR you can sparge and boil more to improve efficiency. Nothing wrong with either method. Not a trust issue.

 

[SRJHops]

Not exactly. Bigger beers will simply tend to have lower efficiency if you stick close to standard single batch sparge process. You have a choice. You can choose to stay close to standard process per your calculator or similar and suffer the lower efficiency, OR you can sparge and boil more to improve efficiency. Nothing wrong with either method. Not a trust issue.

I am on board with the double sparge from now on for sure. But if not a calculator, how should I figure out how much water I really need? How much more is "more"?

I am certain I would have gotten a lot better results had I used 10.40 gallons and collected it all. For my Quad, I used 10 gallons but stopped collecting sparge water when I hit my pre-boil. (The idea was to avoid astringency, but I clearly left sugar behind.). I still probably would have ended up shy of my target OG.

BTW, my Quad is attenuating more due to the extra 8 ounces of brown sugar I threw in to raise the OG. I have a shot at 9.3% apparent ABV (my goal was 9.5). Will be right at the bottom of the style guidelines at 1.010 FG, but the Trappists would say that's very digestible.

 

[SRJHops]

Time to complete conversion in the mash is highly dependent on the crush coarseness or fineness. Fine crushes can achieve complete conversion in 20-30 minutes, but coarse crushes (most supplier crushes are coarse) may take significantly longer than an hour to complete conversion.

Conversion is a two step process. Before the enzymes can act on the starch chains, the starch must be gelatinized (swollen by the absorption of water - this is what happens when you cook rice or oatmeal.) Once (at least the surface of) a starch grain is gelatinized, then the enzymes can come in contact with the starch molecules, in the presence of water to cleave chain bonds. Each bond that is cleaved requires one water molecule to complete the reaction. You have to cleave lots of bonds to convert starch to fermentable sugar.

The gelatinization step is the rate controlling step. Actual hydrolysis (the bond cleaving) happens quite quickly. Gelatinization starts at the surface of grain grits, and proceeds towards the center. The larger the grit, the longer it takes to completely gelatinize. And, you cannot have complete conversion without complete gelatinization.

There are many threads on HBT asking "why is my efficiency so low?" When enough data is available for diagnosis, it often turns out that conversion efficiency is much lower than 100%, and this is almost always because the mash was too short for the coarseness of the grain crush. I have seen one case where the mash pH was way out of whack (much less than 5.0) that had almost no conversion, but that is a rare case.

Conversion can be monitored quantitatively by measuring the SG of the wort during the mash. For accurate results the wort must be well homogenized (aggressive stirring or recirculation) before taking SG samples. Take a sample every 15 minutes (you can start after 30 or 45 minutes if you wish), and when the SG doesn't increase between samples, the mash is done. A refractometer is very handy for this kind of sampling. Turns out the maximum SG of the mash wort is only a function of the weighted average grain potential and the mash thickness (water to grain ratio.) Since most typical mashes have weighted potentials of about 37 points/lb (or 80% max extract) it's possible to create a table that shows max mash SG vs. mash thickness (in qt/lb.) When you hit max SG, your mash is done. Here is such a table:

Specific Gravity at 100% conversion for various mash thicknesses​
​	​	​
Mash Thickness (qt/lb)​	Max °Plato​	Max SG​
0.75​	33.0​	1.1436​
0.80​	31.6​	1.1367​
0.85​	30.3​	1.1304​
0.90​	29.1​	1.1247​
0.95​	28.0​	1.1195​
1.00​	26.9​	1.1147​
1.05​	26.0​	1.1103​
1.10​	25.1​	1.1062​
1.15​	24.3​	1.1023​
1.20​	23.5​	1.0988​
1.25​	22.8​	1.0955​
1.30​	22.1​	1.0924​
1.35​	21.5​	1.0895​
1.40​	20.8​	1.0868​
1.45​	20.3​	1.0842​
1.50​	19.7​	1.0818​
1.55​	19.2​	1.0795​
1.60​	18.7​	1.0774​
1.65​	18.3​	1.0753​
1.70​	17.8​	1.0734​
1.75​	17.4​	1.0715​
1.80​	17.0​	1.0698​
1.85​	16.6​	1.0681​
1.90​	16.3​	1.0665​
1.95​	15.9​	1.0650​
2.00​	15.6​	1.0636​
2.05​	15.2​	1.0622​
2.10​	14.9​	1.0609​
2.15​	14.6​	1.0596​
2.20​	14.4​	1.0584​
2.25​	14.1​	1.0572​
2.30​	13.8​	1.0561​
2.35​	13.6​	1.0550​
2.40​	13.3​	1.0539​
2.45​	13.1​	1.0529​
2.50​	12.9​	1.0520​
2.55​	12.6​	1.0511​
2.60​	12.4​	1.0502​
2.65​	12.2​	1.0493​
2.70​	12.0​	1.0484​
2.75​	11.8​	1.0476​
2.80​	11.6​	1.0469​
2.85​	11.5​	1.0461​
2.90​	11.3​	1.0454​
2.95​	11.1​	1.0447​
3.00​	10.9​	1.0440​
3.05​	10.8​	1.0433​
3.10​	10.6​	1.0427​
3.15​	10.5​	1.0420​
3.20​	10.3​	1.0414​
3.25​	10.2​	1.0408​
3.30​	10.1​	1.0402​
3.35​	9.9​	1.0397​
3.40​	9.8​	1.0391​
3.45​	9.7​	1.0386​
3.50​	9.5​	1.0381​
3.55​	9.4​	1.0376​
3.60​	9.3​	1.0371​
3.65​	9.2​	1.0366​
3.70​	9.1​	1.0362​
3.75​	9.0​	1.0357​
3.80​	8.8​	1.0353​
3.85​	8.7​	1.0348​
3.90​	8.6​	1.0344​
3.95​	8.5​	1.0340​
4.00​	8.4​	1.0336​

Brew on

That makes sense, to measure the SG and when it stops changing the mash is done.

I'm a long way from understanding your chart though. Isn't the max SG also highly dependant on the amount of grain?

I'm also thinking of the brewer in the All-Stars book who only brews big beers, usually OG 1.100+. He uses a mash thickness of 2.0. If the max SG at 2.0 is 1.0636, and that is before sparging, I have to wonder what his pre-boil gravity is, how much wort he collects, and how long he boils.

It would seem hard to get a very high pre-boil gravity if your max SG from the mash water is 1.0636.

The chart is just for the mash, correct? So it's hard to know what the sparge water will do to the final pre-boil gravity?

 

[doug293cz]

That makes sense, to measure the SG and when it stops changing the mash is done.

I'm a long way from understanding your chart though. Isn't the max SG also highly dependant on the amount of grain?

If I mash 10 lb of grain with 5 gal of water, shouldn't I get the same SG as I would mashing 20 lb of grain with 10 gal of water? In both cases the mash thickness is 2 qt/lb. On the other hand if I mash 20 lb of grain with 5 gal of water (1 qt/lb), the SG will be much higher than when I mashed 10 lb with the same amount of water. It's not just the amount of grain, but also the amount of water. Increasing grain alone increases SG, increasing water alone decreases SG. Increasing them both in proportion keeps the SG constant.

I'm also thinking of the brewer in the All-Stars book who only brews big beers, usually OG 1.100+. He uses a mash thickness of 2.0. If the max SG at 2.0 is 1.0636, and that is before sparging, I have to wonder what his pre-boil gravity is, how much wort he collects, and how long he boils.

It would seem hard to get a very high pre-boil gravity if your max SG from the mash water is 1.0636.

Yes, that brewer needs to boil off a lot in order to reach SG. If they sparge after mashing at 2 qt/lb, they have to boil off even more water.

The chart is just for the mash, correct? So it's hard to know what the sparge water will do to the final pre-boil gravity?

Yes, the chart is just for the mash, before any run-off, or sparge water added.

Knowing what sparging will do is pretty straight forward for batch sparging. The calculations for this are what my spreadsheet does. If you are interested, I can explain things in gory detail.

For fly sparging, things are more complex, but a realization that many small batch sparges will approximate a fly sparge, allows the use of the batch sparge calculations to get a reasonably accurate estimation of what a fly sparge will do to total wort SG.

Brew on

 

[sibelman]

I decided to have a look at the lovely spreadsheet @doug293cz created to simulate mash&lauter. Recalling previous discussion about these matters, it occurred to me that the simulation/model could be tested and, perhaps, refined by weighing the mashtun after each sparge.

 

[SRJHops]

If I mash 10 lb of grain with 5 gal of water, shouldn't I get the same SG as I would mashing 20 lb of grain with 10 gal of water? In both cases the mash thickness is 2 qt/lb. On the other hand if I mash 20 lb of grain with 5 gal of water (1 qt/lb), the SG will be much higher than when I mashed 10 lb with the same amount of water. It's not just the amount of grain, but also the amount of water. Increasing grain alone increases SG, increasing water alone decreases SG. Increasing them both in proportion keeps the SG constant.



Yes, that brewer needs to boil off a lot in order to reach SG. If they sparge after mashing at 2 qt/lb, they have to boil off even more water.


Yes, the chart is just for the mash, before any run-off, or sparge water added.

Knowing what sparging will do is pretty straight forward for batch sparging. The calculations for this are what my spreadsheet does. If you are interested, I can explain things in gory detail.

For fly sparging, things are more complex, but a realization that many small batch sparges will approximate a fly sparge, allows the use of the batch sparge calculations to get a reasonably accurate estimation of what a fly sparge will do to total wort SG.

Brew on

Thanks. So a few questions:

Why do you think he uses 2 qt/lb for mash thickness? He must erroneously believe it increases fermentability?

How can I figure out how much water to use? Is the calculator I posted unreliable for high gravity beers?

Is your spreadsheet showing the max SG after the sparge too? If so, that would be a pretty straightforward way to determine if the mash thickness is going to work for a specific beer.

 

[doug293cz]

I decided to have a look at the lovely spreadsheet @doug293cz created to simulate mash&lauter. Recalling previous discussion about these matters, it occurred to me that the simulation/model could be tested and, perhaps, refined by weighing the mashtun after each sparge.

Much easier to just compare measured wort volumes and SGs vs. predicted, and this has been done several times over the years for batch sparging.

Brew on

 

[InspectorJon]

Here is another data point regarding high ABV beers, admittedly this is not about 9% beer, more like 11%. The information below was related to a big stout I was working on.

Regarding the low mash temperature: Alvarado Street Brewery in Monterey, CA area brews a lot of strong pastry stouts. I emailed J.C. Hill, their brewer about one I particularly liked and this was a valuable part of his response:

OG was around 33ish, finished around 13 (1.144 to 1.053) or so. Boiled for 5-6 hrs to get it that high without adding DME or LME. We mashed low, around 145, to make sure our wort sugar composition was as simple as possible to get it to "dry" as far as it could go. With these stouts they can stall rather high and leave you with a beer that's unpalatable (but good barrel candidates).

 

[doug293cz]

Why do you think he uses 2 qt/lb for mash thickness. He must erroneously believe it increases fermentability.

I have no idea, you'd have to ask him.

How can I figure out how much water to use? Is the calculator I posted unreliable for high gravity beers?

That calculator does not tell you whether or not you will reach your target OG. It only looks at volumes. My spreadsheet does volumes and predicts SGs throughout the process, including OG. The linked calculator has some other issues, which I will address in another post.

Is your spreadsheet showing the max SG after the sparge too? If so, that would be a pretty straightforward way to determine if the mash thickness is going to work.

My spreadsheet calculates the SG of the wort from each run-off, the pre-boil SG (combination of all run-offs), and the OG (post-boil SG.) It will tell you if you can hit your target OG.

Brew on

 

[SRJHops]

doug293cz​

Sorry, I should have been more clear. I was talking about your table showing 100% Conversion and the different mash thickness and corresponding max SGs. I was trying to understand how to use it. It seemed to me that thinner mashes might make it really hard to reach high pre-boil SGs.

 

[SRJHops]

Here is another data point regarding high ABV beers, admittedly this is not about 9% beer, more like 11%. The information below was related to a big stout I was working on.

Regarding the low mash temperature: Alvarado Street Brewery in Monterey, CA area brews a lot of strong pastry stouts. I emailed J.C. Hill, their brewer about one I particularly liked and this was a valuable part of his response:

OG was around 33ish, finished around 13 (1.144 to 1.053) or so. Boiled for 5-6 hrs to get it that high without adding DME or LME. We mashed low, around 145, to make sure our wort sugar composition was as simple as possible to get it to "dry" as far as it could go. With these stouts they can stall rather high and leave you with a beer that's unpalatable (but good barrel candidates).

Makes sense... My question remains as to how to figure out how much water to collect for the boil-off, though. Or maybe the only way is to just do it and figure it out. The problem is that my brewing calendar is so full that I only brew the Quad once a year...

 

[doug293cz]

doug293cz​

Sorry, I should have been more clear. I was talking about your table showing 100% Conversion and the different mash thickness and corresponding max SGs. I was trying to understand how to use it. It seemed to me that thinner mashes might make it really hard to reach high pre-boil SGs.

In general, when you are doing high gravity beers, you want to mash as thick as you can handle, and sparge as much as possible. When batch sparging, doing 2 or 3 sparge steps will help compared to a single sparge step. Then boil down to your target OG.

Another option is to partygyle. Do a thick mash, no sparge to get the main big beer, and then sparge to create lower gravity wort for a second lower gravity beer.

Brew on

 

[SRJHops]

In general, when you are doing high gravity beers, you want to mash as thick as you can handle, and sparge as much as possible. When batch sparging, doing 2 or 3 sparge steps will help compared to a single sparge step. Then boil down to your target OG.

Another option is to partygyle. Do a thick mash, no sparge to get the main big beer, and then sparge to create lower gravity wort for a second lower gravity beer.

Brew on

Thanks. How can I figure out how much water to use? Or should I just use that calculator I found? Mash and Sparge Infusion Water Calculator | Brewgr

Maybe I was really close without knowing it... The calculator I found says I should have used 10.28 gallons. I actually used 10 (I was guessing), but I left some sparge water/wort in the tun when I hit my pre-boil volume of 7 gallons. If I would have used 10.28 gallons, done a double sparge, collected all the runnings (probably a total of 7.5 gallons), extended the boil to 2 hours, then I might have been in the ballpark for my OG. Right?

 

[doug293cz]

Thanks. How can I figure out how much water to use? Or should I just use that calculator I found? Mash and Sparge Infusion Water Calculator | Brewgr

Maybe I was really close without knowing it... The calculator I found says I should have used 10.28 gallons. I actually used 10 (I was guessing), but I left some sparge water/wort in the tun when I hit my pre-boil volume of 7 gallons. If I would have used 10.28 gallons, done a double sparge, collected all the runnings (probably a total of 7.5 gallons), extended the boil to 2 hours, then I might have been in the ballpark for my OG. Right?

That calculator won't tell you how to hit your brew targets. My spreadsheet will. Here is how I would proceed:

1. Determine what your target OG is
2. Determine what your maximum tolerable boil time is
3. Fill in the input section of my spreadsheet
   • Enter 20 lb for Grain Weight
   • Leave Grain Potential at 37 (unless you have specific data for your recipe)
   • Leave Grain Moisture at 4%
   • Enter your desired Post-Boil Volume
   • Enter your typical Boil-Off Rate
   • Enter your Boil Time from step # 2 above
   • Enter 1.2 as your Min Water/Grain Ratio
   • Enter 0.12 for Apparent Grain Absorption
   • Enter 0 for MLT Undrainable Volume (unless you know a different value for your MLT)
   • Enter 2 for Sparge Steps
   • Enter 95% for Conversion Efficiency
4. Use the "Goal Seek" function as described in this post to recalculate how much grain you actually need given the other inputs above. Use your Target OG from step # 1 above as the Target Value in Goal Seek.

Now you can use the Grain Weight and Volumes from above if they seem acceptable to you. Or, you can reduce your boil time if you are ok with using more grain that calculated in step # 4. If so, then you need to adjust your boil time input downwards and repeat step # 4. If the original results say you need more grain than you want to use, then your options are to increase boil time, reduce post-boil volume, or try a thicker mash (lower Water/Grain Ratio) until you have a set of parameters acceptable to you.

Brew on

 

[dbayub]

That calculator won't tell you how to hit your brew targets. My spreadsheet will. Here is how I would proceed:

1. Determine what your target OG is
2. Determine what your maximum tolerable boil time is
3. Fill in the input section of my spreadsheet
   • Enter 20 lb for Grain Weight
   • Leave Grain Potential at 37 (unless you have specific data for your recipe)
   • Leave Grain Moisture at 4%
   • Enter your desired Post-Boil Volume
   • Enter your typical Boil-Off Rate
   • Enter your Boil Time from step # 2 above
   • Enter 1.2 as your Min Water/Grain Ratio
   • Enter 0.12 for Apparent Grain Absorption
   • Enter 0 for MLT Undrainable Volume (unless you know a different value for your MLT)
   • Enter 2 for Sparge Steps
   • Enter 95% for Conversion Efficiency
4. Use the "Goal Seek" function as described in this post to recalculate how much grain you actually need given the other inputs above. Use your Target OG from step # 1 above as the Target Value in Goal Seek.

Now you can use the Grain Weight and Volumes from above if they seem acceptable to you. Or, you can reduce your boil time if you are ok with using more grain that calculated in step # 4. If so, then you need to adjust your boil time input downwards and repeat step # 4. If the original results say you need more grain than you want to use, then your options are to increase boil time, reduce post-boil volume, or try a thicker mash (lower Water/Grain Ratio) until you have a set of parameters acceptable to you.

Brew on

 

[InspectorJon]

I have not used @doug293cz ’s spreadsheet. From the inputs it looks pretty similar to the Priceless Calculator. I have used that one a lot and find it to be quite accurate. Instead of actual kettle volume you could set that number to reflect a 1 or 1.2 lb/qt grain/water ratio. It will then give you sparging volume, which you could divide into two or three batches. Be sure to change the default numbers to reflect your system.

 

[SRJHops]

That calculator won't tell you how to hit your brew targets. My spreadsheet will. Here is how I would proceed:

1. Determine what your target OG is
2. Determine what your maximum tolerable boil time is
3. Fill in the input section of my spreadsheet
   • Enter 20 lb for Grain Weight
   • Leave Grain Potential at 37 (unless you have specific data for your recipe)
   • Leave Grain Moisture at 4%
   • Enter your desired Post-Boil Volume
   • Enter your typical Boil-Off Rate
   • Enter your Boil Time from step # 2 above
   • Enter 1.2 as your Min Water/Grain Ratio
   • Enter 0.12 for Apparent Grain Absorption
   • Enter 0 for MLT Undrainable Volume (unless you know a different value for your MLT)
   • Enter 2 for Sparge Steps
   • Enter 95% for Conversion Efficiency
4. Use the "Goal Seek" function as described in this post to recalculate how much grain you actually need given the other inputs above. Use your Target OG from step # 1 above as the Target Value in Goal Seek.

Now you can use the Grain Weight and Volumes from above if they seem acceptable to you. Or, you can reduce your boil time if you are ok with using more grain that calculated in step # 4. If so, then you need to adjust your boil time input downwards and repeat step # 4. If the original results say you need more grain than you want to use, then your options are to increase boil time, reduce post-boil volume, or try a thicker mash (lower Water/Grain Ratio) until you have a set of parameters acceptable to you.

Brew on

Cool - I am giving it a go! If I already have a target grain amount I don't need to use the Goal Seek function, correct? (If I still need to use the Goal Seek function, I am having trouble understanding where it is located on the spreadsheet.)

How do I deal with added sugar? I have 2 lbs of D-180 in this recipe. Is there a rule of thumb, perhaps, as to how many pounds of grain is equal to 1 lb of sugar? Of course, there are different sugars... but maybe there's an average/rule of thumb?

I used my actual grain amount for this recipe, which is 19.25. So far your calculator is showing that I need 10.06 gallons of water; 6 gals for strike and 4 gallons (2 gallons X 2 sparges) to reach an SG of 1.085, which is just shy of my original target of 1.088. (I put in a 90 min boil, which is what I always do for my system.)

Those totals are very close to what I actually did (10 gallons water), but I didn't do the double sparge and I left some wort in the sparge tun. BUT it will be interesting to see what you tell me about how to add in the 2 lbs of sugar to the calculations...

P.S. I put in .25 gallons undrainable for the MLT. Maybe I should up that to .5.

 

[SRJHops]

I have not used @doug293cz ’s spreadsheet. From the inputs it looks pretty similar to the Priceless Calculator. I have used that one a lot and find it to be quite accurate. Instead of actual kettle volume you could set that number to reflect a 1 or 1.2 lb/qt grain/water ratio. It will then give you sparging volume, which you could divide into two or three batches. Be sure to change the default numbers to reflect your system.

Thanks, I will give it a look. I do like his kettle volume target, because I have been using kettle efficiency for my recipe development target.

 

[DonT]

I've used @doug293cz "s spreadsheet for a while now. It gets me pretty close and I fly sparge too. But I do have a question I've been meaning to ask... how do you account for added sugars during the boil?

 

[doug293cz]

I have not used @doug293cz ’s spreadsheet. From the inputs it looks pretty similar to the Priceless Calculator. I have used that one a lot and find it to be quite accurate. Instead of actual kettle volume you could set that number to reflect a 1 or 1.2 lb/qt grain/water ratio. It will then give you sparging volume, which you could divide into two or three batches. Be sure to change the default numbers to reflect your system.

There is a reason for this. Mr. Price asked me for a copy of my spreadsheet before I had published it for general availability. Mr. Price built a web page based on the formulas in my sheet. If you look down at the bottom of the page on his site, you will see that he acknowledges me. He also added some other useful features, such as strike water temperature calculations, hop absorption, etc. I use the Priceless calculator for doing my strike temp calculations.

Brew on

 

[SRJHops]

There is a reason for this. Mr. Price asked me for a copy of my spreadsheet before I had published it for general availability. Mr. Price built a web page based on the formulas in my sheet. If you look down at the bottom of the page on his site, you will see that he acknowledges me. He also added some other useful features, such as strike water temperature calculations, hop absorption, etc. I use the Priceless calculator for doing my strike temp calculations.

View attachment 812968

Brew on

I can't get his to work, but it appears to be for BIAB anyway - not sure if the metrics are the same? In any case, yours seems better...

Did you see our questions about how to account for added sugar to the boil?

When I used your calculator I got a predicted OG of 1.085. But that was without the 2 lbs of D-180. Not sure how many points I'd get from that sugar, but I'm guessing it would now put me over my target OG of 1.088.