Sparge Absorption?

[doublehaul]

I posed this question in another thread and thought I would start a thread to ask -

Is this possible? - on my last batch -

mashed with ~ 3.7 gallons, collected 1.5
sparged with 5.5, thinking I'd end with 7 total - but collected 4, bringing volume up to 5.5
so i had to sparge again to hit just under 7 total.

I have a standard 10 gallon igloo round cooler with ss braid.

I would think my deadspace would have been full and grain absorption done, and i would have got 5.5 out of the 1st sparge, for a total of 7. This was a WIT - with wheat and oats, but it seems like I had this same issue on the previous batch so I tried to pay closer attention and took notes on the volumes.

on a side note, by OG was right on.

 

[hops2it]

You batch sparging? Losing 1.5 gallons to absorption at that point seems really odd, I see almost zero loss. And you're right, dead space would be full from the strike water/mash. I don't get it.

 

[Stauffbier]

Sometimes the last gallon or two can take a long time to drain from batch sparging. I usually leave the valve open with the hose in my kettle while I start the boil. You really shouldn't lose any liquid to the grist during the sparge. Since you're using wheat and oats you might benefit from using rice hulls if you don't already. If you do, then use a little more!

 

[hops2it]

What are you using to measure your gallons of water added? Are you using a different means to measure total wort output?

 

[doublehaul]

What are you using to measure your gallons of water added? Are you using a different means to measure total wort output?

A wooden dowel with marks for every gallon in my boil pot. I filled my pot with water a gallon at a time and marked - and yes - I use the same means/pot for total output. Maybe I am being impatient on my sparge but it sure appear to be done by the appearance of the grain bed, no more flow, etc. This was my 3rd all grain batch - I am still getting dialed in

 

[hops2it]

A wooden dowel with marks for every gallon in my boil pot. I filled my pot with water a gallon at a time and marked - and yes - I use the same means/pot for total output. Maybe I am being impatient on my sparge but it sure appear to be done by the appearance of the grain bed, no more flow, etc. This was my 3rd all grain batch - I am still getting dialed in

Well here's the thing, 1.5 gallons of unaccounted for liquid is going to be highly noticeable in that cooler. How do you dispose of your grains? Are you scooping them out or do you just dump them somewhere or start rinsing them right away with a hose or something? That's the only way I can imagine you not noticing all that liquid in there upon cleanup because we're talking about 15% of your cooler volume still holding liquid here. In any event, maybe scoop them out next time and see what's going on toward the bottom of your grain bed.

 

[doublehaul]

Well here's the thing, 1.5 gallons of unaccounted for liquid is going to be highly noticeable in that cooler. How do you dispose of your grains? Are you scooping them out or do you just dump them somewhere or start rinsing them right away with a hose or something? That's the only way I can imagine you not noticing all that liquid in there upon cleanup because we're talking about 15% of your cooler volume still holding liquid here. In any event, maybe scoop them out next time and see what's going on toward the bottom of your grain bed.

Good idea ill try that

 

[jkendal]

sometimes the last gallon or two can take a long time to drain from batch sparging. I usually leave the valve open with the hose in my kettle while i start the boil. You really shouldn't lose any liquid to the grist during the sparge. Since you're using wheat and oats you might benefit from using rice hulls if you don't already. If you do, then use a little more!

+1

 

[MW66]

I know that my cooler has .35 gallons dead space and my grain absorption is .10 gallons per pound of grain. Dead space is easy to calculate as I just poured in a gallon into my Ice Cube cooler/mash tun and then opened the spigot and measure how much I got out. So that's the easy part of the equation. Figuring out the grain absorption is a little harder depending on your crush and malt type, but you will be in the neighborhood. Once you know your dead space, just measure your first run from your mash. Volume of mash water - (First run mash volume + Dead space) = Volume of water absorbed by grain. Divide the volume by the grain bill and that should be your factor for absorption in future calculations. Your only variables will be the crush consistency and your grain varieties. I did this calculation on my first batch and it has been consistent everytime at .10 gallons/pound of grain.

 

[RainyDay]

I know that my cooler has .35 gallons dead space and my grain absorption is .10 gallons per pound of grain. Dead space is easy to calculate as I just poured in a gallon into my Ice Cube cooler/mash tun and then opened the spigot and measure how much I got out. So that's the easy part of the equation. Figuring out the grain absorption is a little harder depending on your crush and malt type, but you will be in the neighborhood. Once you know your dead space, just measure your first run from your mash. Volume of mash water - (First run mash volume + Dead space) = Volume of water absorbed by grain. Divide the volume by the grain bill and that should be your factor for absorption in future calculations. Your only variables will be the crush consistency and your grain varieties. I did this calculation on my first batch and it has been consistent everytime at .10 gallons/pound of grain.

This is pretty consistent with what i'm losing. I've got a cooler (rectangle) set up and I count on losing a pint of water per pound of grains due to absorbsion/dead space.

 

[doublehaul]

Brewed another batch - I am having ZERO luck figuring out my equipment. 4th all grain batch - you'd think I had it dialed by now.

Beforehand, I poured a gallon of water in my mash tun and drained it, and then poured what was left in the tun into another container and measured precisely: 59 fluid oz or 1.74 L or .46 gallons. Then, looking at past recipe notes, my grain absorption seemed to be in the standard .1 to .13 range.

So, I just brewed a batch with 14.8 lbs of grain, and I figured loss would be .46 + (14.8 * .1) = about 2 gallons - and it could be more if grain absorption is more. I mashed with a little over 5 1/2 gallons (and I measure this in a plastic bucket fermenter w/ gallon marks. 60 mins later I go to sparge, and collect 4 gallons! So only 1 gallon absorption (.06?) I don't get it.

Then to make matters worse, I sparged and collected just under 7, did a 60 minute boil and ended with 4.5 gallons in the carboy. I had 5.75 ounces of hops which would absorb alot of beer, but is it even possible I could boil off that much?!

 

[MW66]

Are you crushing your own grain? If so, is it a roller mill?

 

[corax]

Then to make matters worse, I sparged and collected just under 7, did a 60 minute boil and ended with 4.5 gallons in the carboy. I had 5.75 ounces of hops which would absorb alot of beer, but is it even possible I could boil off that much?!

It depends on the geometry of your kettle and how vigorous your boil is. My evaporation rate is 2 gallons per hour. You also have to take the dead space in your kettle into consideration.

 

[Stauffbier]

Are you crushing your own grain? If so, is it a roller mill?

It depends on the geometry of your kettle and how vigorous your boil is. My evaporation rate is 2 gallons per hour. You also have to take the dead space in your kettle into consideration.

As mentioned in these two posts, the crush does seem to have an effect on absorption. Grain seems to absorb more if it's a finer crush. IME..
I've also noticed that I will lose more to absorption if I mash longer (say 2 hrs instead of 1hr). I have a theory that the longer the water sits on the grist the more saturated the grist gets. Hence holding more water. Your numbers on mash and sparge don't seem too far off this time around, but the boil volumes are strange. It sounds like your kettle (or firing rate) creates a lot of boil off. Have you tried boiling just 7 gallons of water and measuring the amount of water that's left after an hour? Also, are you possitive that you're starting with 7 gallons? Maybe you should measure out 7 individual gallons with a measuring cup in to the kettle to double check...

 

[RainyDay]

Brewed another batch - I am having ZERO luck figuring out my equipment. 4th all grain batch - you'd think I had it dialed by now.

Beforehand, I poured a gallon of water in my mash tun and drained it, and then poured what was left in the tun into another container and measured precisely: 59 fluid oz or 1.74 L or .46 gallons. Then, looking at past recipe notes, my grain absorption seemed to be in the standard .1 to .13 range.

So, I just brewed a batch with 14.8 lbs of grain, and I figured loss would be .46 + (14.8 * .1) = about 2 gallons - and it could be more if grain absorption is more. I mashed with a little over 5 1/2 gallons (and I measure this in a plastic bucket fermenter w/ gallon marks. 60 mins later I go to sparge, and collect 4 gallons! So only 1 gallon absorption (.06?) I don't get it.
Then to make matters worse, I sparged and collected just under 7, did a 60 minute boil and ended with 4.5 gallons in the carboy. I had 5.75 ounces of hops which would absorb alot of beer, but is it even possible I could boil off that much?!

To be honest, that sounds about right, at least to my set-up (75% efficiency - CPVC manifold, Igloo cooler, LHBS grain mill). Considering all of these things working against your efficiency, you can plan to lose about a pint of water per pound of grain, which in this case would be 1.85 gallons, which is in line with what you said. You could either make up the difference with a batch sparge (if you know beforehand what you'll lose, in this case a gallon and a half, then plan to sparge with 3-3.5 gallons of water to get you to 7 gallons preboil volume. This of course depends on how many gallons you lose to the boil.), or if your tun is big enough, just add enough water to not have to batch sparge. It sounds like our systems are pretty similar, so as far as the absorbsion/dead space, just plan on losing a pint of water per pound of grain, adjust your water volume accordingly, and last and most important, RDWHAHB. :rockin:

 

[doublehaul]

Yeah this is all adding up. Thanks for the responses. I had a finer crush than other batches, vigorous boil, and was in direct hot sunlight all boil. Just seems like I boiled off less on a 90 min. boil last time. I don't want to boil water to test because I have a propane burner. And I guess my mash numbers make sense.

 

[Phyrst]

Kind of sounds like you had a stuck sparge. In my last AG batch I thought I had a stuck sparge. I was 1.5 gallons under where I thought I would hit, and I had never had a stuck sparge before. I use the 10 gal rubbermaid cooler with a metal braid hose. I had the valve wide open and it was just dripping out for an hour. Finally, I decided to tip the cooler in case my hose was suspended in the grist and giving me a lot of dead space. When I did, I pulled the cooler back a few inches on the table and suddenly wort came gushing out of the valve. I think my hose was pushing up against the bottom or side of my kettle and restricting the flow and when I moved the cooler it opened it up. Took me about three minutes to collect the final gallon I was looking for.