Grainfather - deadspace

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MarkF_2703
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Grainfather - deadspace

Post by MarkF_2703 » Sat Nov 11, 2017 12:25 pm

A quick question, when transferring wort from the grainfather to the FV do you tilt it over to get an extra litre out or not? I ask because on my first attempt I was 3 litres short on my FV target, 2 I can account for as I got confused and sparged 2 litres short which would have taken me to a 29 litre boil.

aamcle
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Re: Grainfather - deadspace

Post by aamcle » Sat Nov 11, 2017 1:01 pm

If I recall correctly the dead space is 2.7 litres but if you use the GF calculators it should be taken into account.

aamcle

chefgage
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Re: Grainfather - deadspace

Post by chefgage » Sat Nov 11, 2017 2:08 pm

If you use the grainfather app I find i am about 1.5l to 2l short each time. The app/calculator uses i think 0.8 as its grain absorbtion. This is to low but you cannot really change that.

chefgage
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Re: Grainfather - deadspace

Post by chefgage » Sat Nov 11, 2017 2:08 pm

Also the dead space is indeed taken into account when it calculates volumes

MarkF_2703
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Re: Grainfather - deadspace

Post by MarkF_2703 » Sat Nov 11, 2017 4:10 pm

Thanks, its only the first brew and first non kit experience, so early days, just trying to work out how I get bigger FV quantity, I have 30l kegs to fill :D so 27 litres in the FV would be a good target.

Tried the Brewsmith trial, but couldn't really work out what it was telling me as total liquor was around 40 litres :shock:

chefgage
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Re: Grainfather - deadspace

Post by chefgage » Sat Nov 11, 2017 4:51 pm

MarkF_2703 wrote:
Sat Nov 11, 2017 4:10 pm
Thanks, its only the first brew and first non kit experience, so early days, just trying to work out how I get bigger FV quantity, I have 30l kegs to fill :D so 27 litres in the FV would be a good target.

Tried the Brewsmith trial, but couldn't really work out what it was telling me as total liquor was around 40 litres :shock:
I take it you mean beersmith? With that software you can indeed set it up for a grainfather and you could also address the issue with the absorbtion rate (this is easily changed in beer smith). Although i have stopped using beersmith and just use the grainfather to create the recipe then this is then available on the grainfather connect app ready for sending to the grainfather (dont know if you already do this, appologies if you do :) )

I think the max volume the grainfather holds is 30l but that would be to the top :) I think a resonable max boil volume is 27l which takes into account the hot break when coming to boil. So after boil volume is something like 25l. Then with deadspace etc I am left with 22l in the fermenter.

MarkF_2703
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Re: Grainfather - deadspace

Post by MarkF_2703 » Sat Nov 11, 2017 8:54 pm

Yes Beersmith, too much of Pilgrims Hope :D

I am using the Grainfather app, but it is very early days so i thought I would stick with recommended, so if you get 22l in the FV then that is where I should have been or there abouts had I not cocked up the Sparge volume, but with a 90 min boil lots of boil off.

I had an issue with the connect app, when the phone lost connection it never continued on with the program, I had to just run it from the connect box, until I accidentally switched off the Grainfather instead of the sparge heater :oops: just one of the small errors during the day :D

Dave S
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Re: Grainfather - deadspace

Post by Dave S » Mon Nov 13, 2017 11:16 am

The GF calculation for Sparge volume is incorrect. As mentioned above, 0.8 used for grain absorption is wrong. It should be 1.1, and the figure of 2L for dead space is also wrong. That, in my experience is nearer 2.5L, probably due to losses in the CFC and it will vary in any case depending on how many hops are used. It also doesn't take into account shrinkage due to post-boil cooling. Consequently I always calculate my Sparge volume manually and ignore the GF calculation. First work out what your pre-boil volume should be. That will not change for a given brew length and boil time. I usually do 27L brews with a 90 minute boil, so my pre-boil is:-

27 + 2.5(dead space, not GF's value of 2) + 4.5 (3L per hour evaporation) + 1.2 (4% post-boil shrinkage) = 35.2L. This amount will not fit in the GF all at once so I keep a little back and add during the boil.

So your Sparge volume should be:-

Pre-boil vol - Mash vol + (grain weight x 1.1). I use these values every time and my brew length in the FV is almost always bang on.

I've raised this issue with them on numerous occasions but up until now they seem content to ignore me.
Best wishes

Dave

MarkF_2703
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Re: Grainfather - deadspace

Post by MarkF_2703 » Mon Nov 13, 2017 1:06 pm

Thanks Dave, very interesting, does that affect the ABV at all if you are using more water? 27litre would suit me as I have 30 litre kegs.

Very much a beginner at all grain and the GF.

You might need to run this past me again, how do I know my Mash Volume?
Pre-boil vol - Mash vol + (grain weight x 1.1). I use these values every time and my brew length in the FV is almost always bang on.

Dave S
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Re: Grainfather - deadspace

Post by Dave S » Mon Nov 13, 2017 2:12 pm

MarkF_2703 wrote:
Mon Nov 13, 2017 1:06 pm
Thanks Dave, very interesting, does that affect the ABV at all if you are using more water? 27litre would suit me as I have 30 litre kegs.

Very much a beginner at all grain and the GF.

You might need to run this past me again, how do I know my Mash Volume?
Pre-boil vol - Mash vol + (grain weight x 1.1). I use these values every time and my brew length in the FV is almost always bang on.
They have got the Mash volume calculation right. It is:-

(Grain weight x 2.7) + 3.5 (the dead space from the bottom of the grain basket to the bottom of the boiler).

e.g. for a 5kg grain bill it would be 5 x 2.7 = 13.5 + 3.5 = 17L water.

Regarding the brew length, you do have to calculate your recipe for 27L. You can't just top up a 23L recipe with extra water or your ABV and brew body will suffer.
Best wishes

Dave

MarkF_2703
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Re: Grainfather - deadspace

Post by MarkF_2703 » Mon Nov 13, 2017 4:04 pm

Thanks Dave, that makes a bit more sense, I have a 2nd brew to go on which I bought as a kit already meaasured out so will stick with the 23l and try your water calculation for the boil. :D

MarkF_2703
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Re: Grainfather - deadspace

Post by MarkF_2703 » Mon Nov 13, 2017 5:09 pm

Dave, I have just knocked a spreadsheet up using your numbers, seems correct using your 27 litre and 90 minute boil, can you just check the figures I have got for a 23 litre brew and 70 minute boil.

I end up with

Pre boil Vol 30.02 litres
Mash vol 17 litres (5kg)
Sparge Vol 18.52 litres

Adding sparge and mash vol gives me my total liquor? 35.52 litres?

So for a bigger brew I would need to hold back from the sparge the litres over 30 in the preboil vol to add during the boil?

Dave S
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Re: Grainfather - deadspace

Post by Dave S » Mon Nov 13, 2017 7:17 pm

MarkF_2703 wrote:
Mon Nov 13, 2017 5:09 pm
Dave, I have just knocked a spreadsheet up using your numbers, seems correct using your 27 litre and 90 minute boil, can you just check the figures I have got for a 23 litre brew and 70 minute boil.

I end up with

Pre boil Vol 30.02 litres
Mash vol 17 litres (5kg)
Sparge Vol 18.52 litres

Adding sparge and mash vol gives me my total liquor? 35.52 litres?

So for a bigger brew I would need to hold back from the sparge the litres over 30 in the preboil vol to add during the boil?
I get almost the same:

Pre-boil = (23 +2.5)/.96 = 26.56(post-boil before shrinkage) + 4.5 = 31.06L
Mash volume = 17L
Sparge = 31.06 - 17 + (5 x 1.1) = 19.56

Total liquor = 17 + 19.56 = 36.56L
Best wishes

Dave

MarkF_2703
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Re: Grainfather - deadspace

Post by MarkF_2703 » Mon Nov 13, 2017 7:37 pm

Dave S wrote:
Mon Nov 13, 2017 7:17 pm
MarkF_2703 wrote:
Mon Nov 13, 2017 5:09 pm
Dave, I have just knocked a spreadsheet up using your numbers, seems correct using your 27 litre and 90 minute boil, can you just check the figures I have got for a 23 litre brew and 70 minute boil.

I end up with

Pre boil Vol 30.02 litres
Mash vol 17 litres (5kg)
Sparge Vol 18.52 litres

Adding sparge and mash vol gives me my total liquor? 35.52 litres?

So for a bigger brew I would need to hold back from the sparge the litres over 30 in the preboil vol to add during the boil?
I get almost the same:

Pre-boil = (23 +2.5)/.96 = 26.56(post-boil before shrinkage) + 4.5 = 31.06L
Mash volume = 17L
Sparge = 31.06 - 17 + (5 x 1.1) = 19.56

Total liquor = 17 + 19.56 = 36.56L
We are a liter adrift for some reason, not sure I follow the /.96 bit? I am working on a 50ml evap per minute which should equate to 3l an hour in the boil, so I can have the boil time as a variable on the spreadsheet. I am working the 4% shrinkage out after the evaporation of 3.5litres, was never good at maths at school and that was an awful long time ago. #-o

(23+2.5)*4% gives shrinkage of 1.02 litres plus 3.5 evap so 23+2.5+1.02+3.5=30.02 I may be confused here :D

Any minute now I am going to feel a right idiot :D

Dave S
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Re: Grainfather - deadspace

Post by Dave S » Tue Nov 14, 2017 11:21 am

MarkF_2703 wrote:
Mon Nov 13, 2017 7:37 pm
Dave S wrote:
Mon Nov 13, 2017 7:17 pm
MarkF_2703 wrote:
Mon Nov 13, 2017 5:09 pm
Dave, I have just knocked a spreadsheet up using your numbers, seems correct using your 27 litre and 90 minute boil, can you just check the figures I have got for a 23 litre brew and 70 minute boil.

I end up with

Pre boil Vol 30.02 litres
Mash vol 17 litres (5kg)
Sparge Vol 18.52 litres

Adding sparge and mash vol gives me my total liquor? 35.52 litres?

So for a bigger brew I would need to hold back from the sparge the litres over 30 in the preboil vol to add during the boil?
I get almost the same:

Pre-boil = (23 +2.5)/.96 = 26.56(post-boil before shrinkage) + 4.5 = 31.06L
Mash volume = 17L
Sparge = 31.06 - 17 + (5 x 1.1) = 19.56

Total liquor = 17 + 19.56 = 36.56L
We are a liter adrift for some reason, not sure I follow the /.96 bit? I am working on a 50ml evap per minute which should equate to 3l an hour in the boil, so I can have the boil time as a variable on the spreadsheet. I am working the 4% shrinkage out after the evaporation of 3.5litres, was never good at maths at school and that was an awful long time ago. #-o

(23+2.5)*4% gives shrinkage of 1.02 litres plus 3.5 evap so 23+2.5+1.02+3.5=30.02 I may be confused here :D

Any minute now I am going to feel a right idiot :D
Yes, the 0.96 is the shrinkage. It shrinks from 26.56 to 25.5. So the shrinkage is 1.06L
Best wishes

Dave

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