Metric brewers, what's your absorption and batch volume?

[pricelessbrewing]

Finally getting around to updating my mash calculator for metric, and need two small bits of info.

What are most recipes formulated to in regards to the volume into fermenter (Batch volume)?

19L, 20L, 21L?

What's your absorption rate usually?

Us americans use 0.08gal/lb pretty much exclusively, except for that

Paging Gavin to the front desk please, Gavin Come in.

guy since he's a strange hulk-brewer who gets down to 0.04 ga/llb

Should I convert that to SI units? If so it's ~0.66 L/Kg, and 0.33 L/Kg respectively. Is that pretty typical? Or do you have another typical absorption rate?

 

[McKnuckle]

I use 0.06 gal/lb for my BIAB no-squeeze calculations. I determined it a while back by weighing the dry grain en masse, going through the brew process, and then weighing the wet grain en masse after brewing. Simple subtraction gets you the weight of the absorbed water, which is easily converted to gallons (3.785 kg/gal).

I gravity drain until boiling starts, then put the bag on a strainer over a pail. I pour in the drippings a couple of times and then call it a day.

I'm sure the rate varies by a tiny amount, but so far this aspect of my calculations has been solid across a bunch of brews.

 

[Gavin C]

Finally getting around to updating my mash calculator for metric, and need two small bits of info.

What are most recipes formulated to in regards to the volume into fermenter (Batch volume)?

19L, 20L, 21L?

What's your absorption rate usually?

Us americans use 0.08gal/lb pretty much exclusively, except for that guy since he's a strange hulk-brewer who gets down to 0.04 ga/llb

Should I convert that to SI units? If so it's ~0.66 L/Kg, and 0.33 L/Kg respectively. Is that pretty typical? Or do you have another typical absorption rate?

I've been stating 0.045g/lb absorption for a long time but I need to correct that error now. Since I started correcting my true preboil volume measure to allow for volumetric shrinkage to the same temperature as when I measure the strike volume it is more like 0.055g/lb

0.08 gal/lb absorption is much higher than I see without any special measures being taken.

ETA: Just saw this post by chance. Seems like it would be a simple conversion in your calculator SI units to silly imperial and vice versa. (I use the silly ones as that is all I've used as a brewer)

Simple subtraction gets you the weight of the absorbed water, which is easily converted to gallons (3.785 kg/gal).

Not so

Initial grain weight - weight of extracted sugars + weight of absorbed sweet-wort = Weight of grain after mash, squeeze etc. (The weight that goes in the flowerbeds/trash can)

The weight of discarded grain can in theory be comparable or even less than the weight of the initial dry grain.

 

[McKnuckle]

I understand that correction - it makes sense. I'm in no position to weigh sugar, though, so I accept my dumbed-down version for practical purposes. No way my discarded grain is lighter than the dry grain, though. Hard to imagine that happening.

 

[Gavin C]

I understand that correction - it makes sense. I'm in no position to weigh sugar, though, so I accept my dumbed-down version for practical purposes. No way my discarded grain is lighter than the dry grain, though. Hard to imagine that happening.

Say you have 30L of preboil wort at 1.040 (~110g/L)

Thats 110g x 30 = 3.3kg of sugar removed from the grain remaining in the BK.

(More sugars actually removed from the grain as you will have sugars in sweet wort absorbed by the grain too)

 

[McKnuckle]

How do you come up with 110g/L @ 1.040? I assume it's gravity points-dependent but I can't determine the base rate from this one example.

Anyway if you are now using 0.055 gal/lb, then my 0.06 is close enough for me.

 

[Gavin C]

How do you come up with 110g/L @ 1.040? I assume it's gravity points-dependent but I can't determine the base rate from this one example.

Anyway if you are now using 0.055 gal/lb, then my 0.06 is close enough for me.

The number is taken from this table.

I used it as an example many of us are familiar with for making starters. 100g/L of wort works out to about ~1.040 and 110g/L

(Volume of wort is 1L, volume of water added to DME to reach 1L is less than that as DME itself has volume)

I'm not trying to suggest your figure of 0.06 is incorrect. However, your calculations to reach that figure do not reflect what's happening. That's all I wanted to point out.

Sorry for the thread tangent.

 

[pricelessbrewing]

it is more like 0.055g/lb

0.08 gal/lb absorption is much higher than I see without any special measures being taken.

ETA: Just saw this post by chance. Seems like it would be a simple conversion in your calculator SI units to silly imperial and vice versa. (I use the silly ones as that is all I've used as a brewer)

Cool, thanks Gavin. I've been meaning to go through the math and see where that points you in relation to the starting grain weight, and moisture content.

BTW does the quote I'm using show up as a notification, since I can't do @GavinC or does having the wrong thread throw it off?

 

[Gavin C]

Cool, thanks Gavin. I've been meaning to go through the math and see where that points you in relation to the starting grain weight, and moisture content.

BTW does the quote I'm using show up as a notification, since I can't do @GavinC or does having the wrong thread throw it off?

This quote did show up. The other one I just saw by chance. Thought the thread title was odd so clicked it. (Not trying to suggest your thread is odd)

 

[pricelessbrewing]

This quote did show up. The other one I just saw by chance. Thought the thread title was odd so clicked it. (Not trying to suggest your thread is odd)

Haters gonna hate. That's annoying, there really should be a way to tag users with spaces in their name... @Gavin%20C ? No dice...

 

[doug293cz]

Cool, thanks Gavin. I've been meaning to go through the math and see where that points you in relation to the starting grain weight, and moisture content.

...

Go back and look at my spreadsheet. To find the weight of the wet grain, just add the retained grain wt to the retained water wt (columns O & P in ver 4.)

Sorry to those of you that don't have the spreadsheet. I really do plan to publish it sometime.

Brew on

 

[pricelessbrewing]

Go back and look at my spreadsheet. To find the weight of the wet grain, just add the retained grain wt to the retained water wt (columns O & P in ver 4.)

Sorry to those of you that don't have the spreadsheet. I really do plan to publish it sometime.

Brew on

Yup, i know it's easily done in there and would only take a minute or so. Just haven't gotten around to actually doing it...