AG Mashing question

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thejuanald

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So I will be doing my first all grain batch this weekend and I've been reading and reading about the process and I had a quick question. I will be doing a batch sparge in a 10 gallon round cooler. Beersmith tells me for 16 lbs of grain, I should mash with 5.80 gallons of water (at 1.25 qts/lb, adjusting for tun dead space), and then sparge with 3.8 gallons up to a total of 6.90 gallons of wort pre-boil, and a fermentation size of 5.40 gallons (accounting for trub loss and boil off).

My question is, I was under the assumption that you should sparge with more water than you mash with. Is this correct or is using less sparge water fine? Also, Is 6.90 gallons pre-boil a good amount? To me it seems like a little much. I feel like I am probably over-thinking this (grad student in engineering currently trying to finish my thesis). Thanks for all the help!

I am pretty much using Yooper's Ruination clone recipe (except I increased the amount of grain and hops a bit) from here: https://www.homebrewtalk.com/f69/stone-ruination-clone-155771/
 
something seems off to me, it looks like you'll have a bit too much mash water. My calculation is 16(lbs) x 1.25 (quarts) = 20 quarts.... or 5 gallons. Also, you are not accounting for grain absorption when calculating out how much wort you will have after the mash. The grains will probably absorb about a gallon or more.
 
You can expect the grain to absorb 0.5 quarts per lb (0.125 gallons per lb) during the mash. Since the grain has absorbed all it can during the mash, you will be able to collect most of the sparge water you add. Because of this I routinely mash with more water than I sparge with. I like to have equal volumes of 1st and 2nd runnings.
 
BlackGoat, his strike water amounts include the MT dead space.

If you use 5.8gal of strike water, my guess is your first runnings will have a volume of about 3.8-4gal. John Palmer (and I believe BeerSmith) says grain absorption is in the range of 0.1gal/lb grain. this would mean 1.6gal for your setup. Your mash tun will not have 0.8gal of deadspace; I believe it will be closer to 0.5gal. That brings us to about 2gal lost in the mash.

if you pull off around 4gal, you'll need to sparge with about 3gal to get near 7gal pre-boil. I have a pot with a large diameter, so I boil off 1.5gal/hr at a rolling boil, so it's definitely not excessive to have 6.9gal as your preboil (I aim for 5.5gal so that my losses to trub leave me with a full 5gal). However, you don't need to worry about Sparge volumes: Fill your BK with water, .5gal at a time. Use a stick, and mark the level for each volume. Now, when you do your lautering, you put the stick in, and see how much you have. preboil-first runnings=roughly amount of strike water.

You may not hit your numbers, and that's fine. What you should really focus on, is to tune in the deadspace in your MT. Keep a log book which notes the water used (sparge+strike), the pre boil volume, and the lbs of grain. You should be able to eventually see a trend of how much isn't being accounted for by absoption (i.e. deadspace). If you wanted to be REALLY technical about it, you could do the following.

Do a number of brews with varying amounts of grain (8-16lbs). Plot loss of water vs. mass of grain used. (i.e. Sparge+Strike-Preboil vs. lbs of grain). This should give you a straight line in the region of 8-16lbs. Extrapolate this line to the Y-axis. This value is your MT dead space. Essentially: Waterloss=L*lbs grain + deadspace. The "L" is the grain absorption, and this is likely how the 0.1gal/lb was determined.


Goodluck!
 
Thanks for the replies, everyone.

BlackGoat, his strike water amounts include the MT dead space.

If you use 5.8gal of strike water, my guess is your first runnings will have a volume of about 3.8-4gal. John Palmer (and I believe BeerSmith) says grain absorption is in the range of 0.1gal/lb grain. this would mean 1.6gal for your setup. Your mash tun will not have 0.8gal of deadspace; I believe it will be closer to 0.5gal. That brings us to about 2gal lost in the mash.

if you pull off around 4gal, you'll need to sparge with about 3gal to get near 7gal pre-boil. I have a pot with a large diameter, so I boil off 1.5gal/hr at a rolling boil, so it's definitely not excessive to have 6.9gal as your preboil (I aim for 5.5gal so that my losses to trub leave me with a full 5gal). However, you don't need to worry about Sparge volumes: Fill your BK with water, .5gal at a time. Use a stick, and mark the level for each volume. Now, when you do your lautering, you put the stick in, and see how much you have. preboil-first runnings=roughly amount of strike water.

You may not hit your numbers, and that's fine. What you should really focus on, is to tune in the deadspace in your MT. Keep a log book which notes the water used (sparge+strike), the pre boil volume, and the lbs of grain. You should be able to eventually see a trend of how much isn't being accounted for by absoption (i.e. deadspace). If you wanted to be REALLY technical about it, you could do the following.

Do a number of brews with varying amounts of grain (8-16lbs). Plot loss of water vs. mass of grain used. (i.e. Sparge+Strike-Preboil vs. lbs of grain). This should give you a straight line in the region of 8-16lbs. Extrapolate this line to the Y-axis. This value is your MT dead space. Essentially: Waterloss=L*lbs grain + deadspace. The "L" is the grain absorption, and this is likely how the 0.1gal/lb was determined.


Goodluck!

Thanks a lot for this post. Everything is much more clear with it. Yeah, looking at beersmith, I was just using the default values for loss to boil, loss to trub, dead space, and loss to fermentation. I will definitely do this experiments and more to gain a more accurate idea of the values for my particular setup.

And thank you for the clarification on sparge water volumes. Why do some resources say you should use up to a 1/2 gallon sparge water per pound of grain?
 
thejuanald said:
Thanks for the replies, everyone.

Thanks a lot for this post. Everything is much more clear with it. Yeah, looking at beersmith, I was just using the default values for loss to boil, loss to trub, dead space, and loss to fermentation. I will definitely do this experiments and more to gain a more accurate idea of the values for my particular setup.

And thank you for the clarification on sparge water volumes. Why do some resources say you should use up to a 1/2 gallon sparge water per pound of grain?

Sparge volumes are not directly dependent upon amounts of grain used.

For example, if you mash with 1.25 qt/lb, or 1.5qt/lb, your sparge volumes will be different as your first runnings will contain different amounts. Come to think of it, 0.5gal per pound of grain doesn't make sense. For a big beer with 14lbs... That's 7 gallons sparge. That would mean you get no water from your mash!

Quick and easy way: mash with 1.25 wt/lb. sparge until you reach pre boil!

Cheers.
 
Sparge volumes are not directly dependent upon amounts of grain used.

For example, if you mash with 1.25 qt/lb, or 1.5qt/lb, your sparge volumes will be different as your first runnings will contain different amounts. Come to think of it, 0.5gal per pound of grain doesn't make sense. For a big beer with 14lbs... That's 7 gallons sparge. That would mean you get no water from your mash!

Quick and easy way: mash with 1.25 wt/lb. sparge until you reach pre boil!

Cheers.

Thanks for the reply, I will definitely follow that rule. I tend to over think things. I have everything to brew next weekend. I will get my starter going probably on Wednesday or Thursday for brewing on saturday.
 
Thanks for the reply, I will definitely follow that rule. I tend to over think things. I have everything to brew next weekend. I will get my starter going probably on Wednesday or Thursday for brewing on saturday.

Thursday will be good, a couple days is plenty of time.

Almost everyone starts out worrying too much! That's why the veterans on this forum love the saying RDWHAHB! It's pretty hard to screw up a beer, honestly. The most important factor is to make sure everything is sanitized properly. If you can fight off an infection, your beer is bound to be a success.

Cheers, and good luck on Saturday!
 
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