From Cooler to Keggle Mash Tun ?

[Ki-ri-n]

So I'm switching from a cooler MT to a keggle. With the cooler, there is virtually no dead space when using a manifold. The keggle has about 1 gallon of Dead space beneath the false bottom. I assume I need to add an extra gallon to the mash water to account for this?

So, if the grain bill is 10 lb, mashing at 1.25 qt/lb = 3.125 gal of mash water. So, would I need 4.125 if using a keggle-right?

 

[max384]

The amount of deadspace should really only affect your lauter volume, not the mash volume. However, if you find that there isn't enough water to cover your grains, you'll need to compensate. If you add a gallon to your mash, you'll create a thinner (higher qt/lb) mash, since the water is still there, and the sugars will mix, as will the enzymes. The thinner mash may not be what you want, depending on what you're doing with your beer.

What John Palmer has to say on the subject of a thinner mash:

"The grist/water ratio is another factor influencing the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer. A thicker mash is more gentle to the enzymes because of the lower heat capacity of grain compared to water. A thick mash is better for multirest mashes because the enzymes are not denatured as quickly by a rise in temperature."

 

[Ki-ri-n]

OK, makes some sense. I usually mash at 1.4 qt/lb. The 1 gallon of dead space really made me think there wouldn't be enough water to cover the whole grain bill and cause all sorts of grief (not what I need on a brew day!). Guess I'll still start where I left off and see what happens. Starting to brew in a bit so thanks for the tip!

 

[brew2enjoy]

I'll chime in on this since I had the same question when I switched to a keggle mash tun. I also have about a gallon below my false bottom. In my mind, if I want the grain dilution to be 1.4 qt/lb there needs to be an extra gallon added first to compensate for the dead space, otherwise you will have a thicker mash. That's what I've been doing for the last 20 or so batches with great results and some award winning beer, so it's working for me.

 

[max384]

I'll chime in on this since I had the same question when I switched to a keggle mash tun. I also have about a gallon below my false bottom. In my mind, if I want the grain dilution to be 1.4 qt/lb there needs to be an extra gallon added first to compensate for the dead space, otherwise you will have a thicker mash. That's what I've been doing for the last 20 or so batches with great results and some award winning beer, so it's working for me.

No offense, but your advice is incorrect. If you add an extra gallon, your mash thickness will be thinner than 1.4 qt/lb. It doesn't matter how thick or thin the mash feels when you are stirring. It only matters what the ratio of water to grain is, regardless of whether you have a false bottom with deadspace or not, since the water, sugars, and enzymes can freely flow between the deadspace and the mash.

 

[brew2enjoy]

No offense, but your advice is incorrect. If you add an extra gallon, your mash thickness will be thinner than 1.4 qt/lb. It doesn't matter how thick or thin the mash feels when you are stirring. It only matters what the ratio of water to grain is, regardless of whether you have a false bottom with deadspace or not, since the water, sugars, and enzymes can freely flow between the deadspace and the mash.

None taken, however I don't completely agree with you. If you want a certain mash thickness you will not achieve it without first filling the deadspace. For example say your grain bill is 15 pounds and you want a mash thickness of 1.25 qt/lb. If you don't compensate for the one gallon below the false bottom your mash consistency is actually closer to .98 qt/lb. How much that matters is subjective and depends on other variables. There is some good info here on mash thickness http://braukaiser.com/wiki/index.php/Understanding_Efficiency#Mash_thickness

I wouldn't call either method "incorrect". A thinner mash is said to have better conversion efficiency, while a thicker mash makes it harder for starches to gelatenize. I say try it both ways and compare the results. That's is really the only way to know what works best for you with your system.

 

[max384]

None taken, however I don't completely agree with you. If you want a certain mash thickness you will not achieve it without first filling the deadspace. For example say your grain bill is 15 pounds and you want a mash thickness of 1.25 qt/lb. If you don't compensate for the one gallon below the false bottom your mash consistency is actually closer to .98 qt/lb. How much that matters is subjective and depends on other variables. There is some good info here on mash thickness http://braukaiser.com/wiki/index.php/Understanding_Efficiency#Mash_thickness

I wouldn't call either method "incorrect". A thinner mash is said to have better conversion efficiency, while a thicker mash makes it harder for starches to gelatenize. I say try it both ways and compare the results. That's is really the only way to know what works best for you with your system.

I disagree with your premise, not your method. There is an argument for both thin and thick mashes.

A mash thickness of 1.25 qt/lb put into either a mash tun with no deadspace or a gallon of deadspace is still 1.25 qt/lb. If you add extra water to compensate for your gallon of deadspace, your mash thickness will be calculated based upon all of the water added, including what goes in the deadspace.

To illustrate my point, if you leave your mash alone, the grain will settle to the bottom and the water will be on top. The grain will feel "thick," but the mash thickness is the same as it was when you mashed in. The water on top of the grain bed is not mixed in amongst the grain, but is still part of the mash. At this point, it is really no different than a deadspace on the bottom, other than when you lauter.

 

[Ki-ri-n]

Hmm, not sure what to think now. Guess I'll have to try it both ways Already brewed once on the new MT at my usual 1.4 qt/# and I do have enough ingredients to replicate that batch but with a thinner mash. I just may have to try that.

I use Brewtarget for my software and I can't see anywhere (other than to adjust the mash thickness) to account for the "dead space" (right, wrong or indifferent). It seams I have a fair amount of sparge water that I could afford to "borrow" some to thin the mash out.

If anyone happens to use a Jaybird FB, what is your typical gap size? Granted there are a lot of other factors that can attribute to this (mill, type 3 vs 2 roller, size of roller, grain conditioning, speed fed through the mill, ect). I currently use a MM2 mill with a gap of 0.039"-0.040". Seems like I can compact the grain bed fairly easily with my pump throttled almost all the way back.

 

[MagicMatt]

None taken, however I don't completely agree with you. If you want a certain mash thickness you will not achieve it without first filling the deadspace. For example say your grain bill is 15 pounds and you want a mash thickness of 1.25 qt/lb. If you don't compensate for the one gallon below the false bottom your mash consistency is actually closer to .98 qt/lb.

No, you've still got it mixed up. The water to gain ratio is just that: a ratio. It is a measure of the amount of two substances with relation to one another. As long as your grain bed it covered by water, it makes no difference the amount of water actually in contact with the grain. If you have 1 gallon of space below your FB and you put in 15 lbs of grain and 15 qts of water, you have a 1qt/lb ratio. If the space below the FB was actually 5 gallons, you'd still have a 1qt/lb ratio - and really how could it be any different if you didn't alter either quantity?

Example: Imagine you had a 100 gallon pot with 99 gallons of space below the false bottom, and wanted to do a 1qt/lb mash with 4lbs of grain. Without taking any false bottoms into account, this would obviously mean you would need 4qts of water for the 4lbs of grain to reach 1qt/lb. But for the grain to be completely submerged with this setup you would need to add 99 gallons to the pot, just so the water will cover the grain. So you're telling me that even though you put in 100 gallons of water and only 4 lbs of grain, that the mash thickness is somehow still 1qt/lb? Somehow all of that water below the FB just gets ignored? Hopefully this helps you see the error in your logic.

Hmm, not sure what to think now. Guess I'll have to try it both ways Already brewed once on the new MT at my usual 1.4 qt/# and I do have enough ingredients to replicate that batch but with a thinner mash. I just may have to try that.

I use Brewtarget for my software and I can't see anywhere (other than to adjust the mash thickness) to account for the "dead space" (right, wrong or indifferent). It seams I have a fair amount of sparge water that I could afford to "borrow" some to thin the mash out.

I think you're confusing "dead space" with "space below the false bottom". Dead space is actually the unrecoverable space - that is, the amount of liquid left after completely draining your MLT via the spigot.

If your dip tube is mounted appropriately, this number should be very low (mine is about 4 floz), and thus essentially negligible. That is the only number we are concerned with regarding dead space, as you'll have to ensure you have enough liquid to still draw your full boil volume. If you have a 1 gallon true dead space, then you will need to add that much extra water to some point of the collection process - either the mash (which will change your thickness), or the sparge (if you don't want to alter the mash thickness).

 

[Ki-ri-n]

I'm not confusing the two, just maybe using them interchangeably and causing some confusion. I don't dispute the actual ratio of water to grain. I think the sticking point is, does it make a difference in a contact ratio? Actual volume of water, in contact with the grain, at a single point in time.

If there's a gallon of space below the false bottom, and you have a grain bill of 3.2 # and mash at 1.25 qts/lb, you only need 1 gallon of water. All of which would be in the space below the false bottom and none in the area of grain. Unless you're recirculating. That's OK?

 

[brew2enjoy]

No, you've still got it mixed up. The water to gain ratio is just that: a ratio. It is a measure of the amount of two substances with relation to one another. As long as your grain bed it covered by water, it makes no difference the amount of water actually in contact with the grain. If you have 1 gallon of space below your FB and you put in 15 lbs of grain and 15 qts of water, you have a 1qt/lb ratio. If the space below the FB was actually 5 gallons, you'd still have a 1qt/lb ratio - and really how could it be any different if you didn't alter either quantity?

Example: Imagine you had a 100 gallon pot with 99 gallons of space below the false bottom, and wanted to do a 1qt/lb mash with 4lbs of grain. Without taking any false bottoms into account, this would obviously mean you would need 4qts of water for the 4lbs of grain to reach 1qt/lb. But for the grain to be completely submerged with this setup you would need to add 99 gallons to the pot, just so the water will cover the grain. So you're telling me that even though you put in 100 gallons of water and only 4 lbs of grain, that the mash thickness is somehow still 1qt/lb? Somehow all of that water below the FB just gets ignored? Hopefully this helps you see the error in your logic.

I understand what you are saying about the water/grain ratio. I guess the question then is not whether the ratio changes but mash thickness, not because of the qt/lb ratio but due to the grain density. In his case (and mine) the grain is condensed and does not come in contact with a portion of the water in the mash tun. Its essentially a "tighter" mash at the same ratio if that makes sense.

 

[MagicMatt]

Correct. Most people use "water to grain ratio" and "mash thickness" interchangeably, and while they might be synonymous/equal at times, they are not always the same thing due to the issue of space beneath a false bottom.