Does 1-1.25 qt./lb. rule account for grain absorption?

I've read conflicting (or ambiguous) advice from various sources, so I'm hoping someone here can clear this up for me. I'm planning on doing my first partial mash this weekend, and I'm trying to figure out how much strike water to start with. The recipe uses 5 lbs. of grain, and I plan to use the higher end of the 1-1.25 qt./lb. ratio to have a "runnier" mash and reduce the risk of a stuck sparge.

So that means I need 6.25 qt. of strike water. However, I'll lose 2 qts. to grain absorption (0.1 gal/lb, right?), which means my first runnings will only be 4.25 qts. Following conventional wisdom that says my batch sparge volume should be equal to my first runnings, I'll also sparge with 4.25 qts.

My question is, should I add that 0.1 gal/qt. of grain absorption on top of my 1.25 * lb. of grain calculation, or is it already accounted for? I mean, since 1.25 * 5 lb. of grain gives me 6.25 qt., and I know my grains will absorb 2 qts, should I be striking with 8.25 qts. instead? Then my first runnings (and sparge) will be 6.25 qt. instead of 4.25 qt. What are you supposed to do here?

kombat said:

I've read conflicting (or ambiguous) advice from various sources, so I'm hoping someone here can clear this up for me. I'm planning on doing my first partial mash this weekend, and I'm trying to figure out how much strike water to start with. The recipe uses 5 lbs. of grain, and I plan to use the higher end of the 1-1.25 qt./lb. ratio to have a "runnier" mash and reduce the risk of a stuck sparge.

So that means I need 6.25 qt. of strike water. However, I'll lose 2 qts. to grain absorption (0.1 gal/lb, right?), which means my first runnings will only be 4.25 qts. Following conventional wisdom that says my batch sparge volume should be equal to my first runnings, I'll also sparge with 4.25 qts.

My question is, should I add that 0.1 gal/qt. of grain absorption on top of my 1.25 * lb. of grain calculation, or is it already accounted for? I mean, since 1.25 * 5 lb. of grain gives me 6.25 qt., and I know my grains will absorb 2 qts, should I be striking with 8.25 qts. instead? Then my first runnings (and sparge) will be 6.25 qt. instead of 4.25 qt. What are you supposed to do here?

Click to expand...

The "rule" isn't 1-1.25 quarts- it's more like 1.25- 2 quarts water per pound. I like a slightly thinner mash, and usually go with 1.5 quarts/pound. But either way is fine.

Anyway, say you use 1.25 quarts/pound. Yes, the grain will absorb about .1 gallon/pound. So, if you have 6.25 quarts you strike with, you'll get out about a gallon of first runnings. Then you sparge with up to 2 quarts per pound, to get up to your boil volume.

In this case, I'd probably mash in with 7.5 quarts (1.5 quarts/pound), as then get 1.35 gallons of first runnings and sparge with the same amount.

I hope that helps!

The mash ratios already account for grain absorption.

For a partial mash though, go ahead and use a higher ratio if you want. eg 1.5, 1.75 etc. All of those will work as long as you don't go crazy (eg gallons per lb or something). The exact volumes are really only important when you are trying to hit an exact volume for your full boil. Since you are going to be adding water and extract anyway, anything in the ballpark will work just fine.

Thanks for the replies, guys, that helps a lot, but brings up another question. Doesn't using a higher ratio compromise extraction efficiency? Given that I'm planning on batch sparging, which isn't the most efficient way to sparge to begin with, wouldn't I want to use a lower mash ratio to try and recover as much efficiency as possible from the mash, knowing I'm going to sacrifice some during sparging? Or should I have simply increased my grain amounts by 10-15% from the outset to account for the efficiency loss of both batch sparging and a higher-ratio mash?

Batch sparging is only slightly less efficient. In fact, i average 80-81% consistently with a single batch sparge AND a thin mash. I actually don't want it to be any more efficient.

So, i wouldnt worry about efficiency as a number to start with. its more important to have a CONSISTENT efficiency, and then tweak accordingly (ie, add more grain, try a thinner/thicker mash, more/less sparge water). But, once you've established consistency, make sure you only 'tweak' one thing at a time, so you can ensure you know what the effect is. you know, the 'scientific process' and so such...

The difference in efficiency is negligible - it really comes down to personal preference and what works best on your system. I personally like to mash thin so that I have to sparge less.

" Doesn't using a higher ratio compromise extraction efficiency?"

No. It generally improves efficiency as long as you can still sparge with enough water and hit your volumes. It is a very common technique to "mash out" - ie add hot water at the end of the mash (before draining or sparging) to heat it up and thin it out.

Sugar (or anything else in solution) moves from areas of high concentration (the grain) to low concentration (the water). Adding more water moves out more sugar. That is the whole idea behind sparging. In all-grain brewing, the limiting factor is the total amount of wort you want to collect. eg 7 gallons. You could get more total sugar out if you collected 8 gallons, but then it would be diluted with an extra gallon of water you don't really want. (You could boil that down and evaporate that gallon before you started your real boil. That is sometimes done with really high gravity beers.)

billl said:

That is sometimes done with really high gravity beers.

Click to expand...

Sometimes it's the only way to get decent efficiency with large grain bills.

kombat said:

Thanks for the replies, guys, that helps a lot, but brings up another question. Doesn't using a higher ratio compromise extraction efficiency? Given that I'm planning on batch sparging, which isn't the most efficient way to sparge to begin with, wouldn't I want to use a lower mash ratio to try and recover as much efficiency as possible from the mash, knowing I'm going to sacrifice some during sparging? Or should I have simply increased my grain amounts by 10-15% from the outset to account for the efficiency loss of both batch sparging and a higher-ratio mash?

Click to expand...

I saw my efficiency go up about 5 points when I increased from 1.25 to 1.75 qt./lb.

I've batch sparged 427 batches as of yesterday and I got 89% efficiency yesterday. I mashed with 1.75 qt./lb. and sparged with about 4.25 gal. for a 5.5 gal. batch. Batch sparging is not necessarily less efficient than fly sparging.

billl said:

" Doesn't using a higher ratio compromise extraction efficiency?"

Click to expand...

I agree with Bill, but there can be a case where a thinner mash could reduce efficiency. If the brewer uses a high alkalinity water and increases the volume of water in the mash, the amount of alkalinity added via that extra water can overwhelm the grain acidity and raise the mash pH. If that pH rise is taken far enough, the extraction and conversion of starches can be reduced.

Considering that alkaline tap water is prevalent for most of the US and many brewers do not adjust their water chemistry, it is conceivable that a loss of efficiency may be observed by some brewers when using a thinner mash. Brewers that know how to adjust their water are probably not going to have an efficiency loss and as pointed out by many in this thread, they are likely to gain efficiency with a thinner mash.

Denny said:

I've batch sparged 427 batches as of yesterday and I got 89% efficiency yesterday.

Click to expand...

Do you keep extensive brewing logs or just make notches in the igloo cooler?

kingwood-kid said:

Do you keep extensive brewing logs or just make notches in the igloo cooler?

Click to expand...

I've filled about 8-9 spiral notebooks at this point. Thought about notching the cooler, but there wouldn't be much left of it at this point!

there was a link posted on here recently that point to a study which proved, with numbers n' science n' stuff, that a thinner mash will extract more than a thicker mash - within reason. essentially, they were getting better efficiency at 1.5 than they were at 1.25.

a very very thin mash can also lead to inefficiency because the enzymes are too diluted and don't make sufficient contact with the starches. i don't think this is a problem until you are well over 2 qt/lb.

sweetcell said:

there was a link posted on here recently that point to a study which proved, with numbers n' science n' stuff, that a thinner mash will extract more than a thicker mash - within reason. essentially, they were getting better efficiency at 1.5 than they were at 1.25.

Click to expand...

Maybe this?

http://braukaiser.com/wiki/index.ph..._Efficiency#Determining_Conversion_Efficiency

Denny, how are you calculating your efficiency? I take it you mean 'extraction efficiency', and not mash efficiency?

Does it include losses from grain absorption, or mash tun dead space loss? Or are you just taking the total water volume that went into the mash?

My sense is you're way overthinking this. I usually mash my full water volume for a 5 gallon batch with no sparge. If I'm doing a 10 gallon batch I will mash with as much water as I can fit comfortably, drain the first runings and measure volume, then sparge with the remaining water and squeeze the grains. The limiting factor is my 15 gallon boilertmaker mash tun/lauter tun/brew kettle.

larrybrewer said:

Denny, how are you calculating your efficiency? I take it you mean 'extraction efficiency', and not mash efficiency?

Does it include losses from grain absorption, or mash tun dead space loss? Or are you just taking the total water volume that went into the mash?

Click to expand...

I first use Kai's chart to calculate conversion efficiency. Then I use Promash too what my total mash efficiency is. Using that, I can find my lauter efficiency. My brewhouse efficiency (which is the number I report when asked about efficiency) takes into account kettle losses and hop absorption.

Wow, so you are getting 89% Brew House Efficiency at home! That is awesome.

You must not have very much deadspace, unless I am missing part of the definition or calculation being done.

Would you agree that extraction efficiency does not count grain absorption, but mash efficiency counts both grain absorption and mash tun dead space?

For example, let's say a brewer mashes 10 pounds of 2-row, which is rated at 37 ppg. That makes for 370 total points available. They mash at a ratio of 1.5qt/lb, which comes out to 3.75 gallons. At 100% efficiency, they would have a gravity of (370 / 3.75 / 1000) + 1 = 1.0987.

Let's say they drain to their kettle, leaving behind 2 quarts in dead space and grain absorption.
Now they have 3.25 gallons at 1.0987. But, at 3.25 gallons, the gravity at 100% efficiency would be (370 / 3.25 / 1000) + 1 = 1.1138,
so now their 'mash efficiency' is 987/1138 = 86%! Does that sound right?

I'd like to know what the most generally accepted calculations are for extraction efficiency, mash efficiency, and brew house efficiency. (Sorry for hijacking the thread OP.)

89% is on the high side of normal for me. It's usually closer to 83-85%. I have virtually no dead space in my cooler...one of the beauties of the braid!

I _think_ I agree with your calculations, but I haven't finished my coffee yet, so I reserve the right to change my mind! And just to make sure we're on the same page, tell me how you define "extraction efficiency".

I'm not actually sure how I define anything anymore. And yes, I am on my second cup up tea!

Extraction efficiency, provisionally, would be:

mash points = (mash gravity - 1) * 1000
theoretical points = (grain weight * ppg) / mash water volume in gallons
mash points / theoretical points = Extraction efficiency



By the way - Eugene is my home town. Go Ducks!

OK, it looks like what I call "mash efficiency". Based on Kai's work, I call it (conversion efficiency)x(lauter efficiency)= mash (or extraction) efficiency. I agree with your definition. Then, when you take kettle losses and hop absorption into account, you get brewhouse efficiency, which I base on gravity and volume into the fermenter. My conversion efficiency is usually near 100% and my mash (extraction) efficiency is usually around the upper 80s to mid 90s. My BHE runs from the mid to upper 80s.

Thanks for the clarification. There are too many efficiency definitions floating around, makes it inefficient... back to brewing.