Calculation Check

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PieOPah

Calculation Check

Post by PieOPah » Tue Sep 05, 2006 3:01 pm

Since I will mainly be Batch Sparging, I wanted to work out the most efficient amounts of water needed.

I assume a lot of you have heard of Denny Conn. If not he is a fairly well known home brewer in the US. Primarily he Batch Sparges. I have taken his figures and converted them into real numbers (stupid American Gallons, Quarts, Pounds etc.)

So, to make things easy for me, I plug in the total amount of grain and this then calculates how much water I need at each stage. I have also allowed for the amount of dead space your Mash Tun may have and how much water the grain absorbs (changeable figures)

Anyway, I would like it if somebody could give the figures a once over and work out whether or not it looks good.

I will be making a few changes along the way, such as adding different volume conversions. I'll also be adding my other little calcs to it.

Thanks

http://www.argentfamily.co.uk/beer/waterneeded.xls

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Andy
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Post by Andy » Tue Sep 05, 2006 3:34 pm

Looks good....

A question though, why the "Top up Volume" addition ? Such a small quantity that it's not worth it is it ? Can't you just up the initial mash liquor quantity or the second sparge quantity to cover it ?

Oh, and you don't need the SUM() part in Excel for normal arithmetic operations, SUM is used to add up ranges of values e.g. SUM(C1:C100) gives you the addition (sum!) of cells C1 through to C100. The SUM expression is redundant where you've used it. B)

BitterTed

Post by BitterTed » Tue Sep 05, 2006 3:39 pm

QUOTE I have taken his figures and converted them into real numbers (stupid American Gallons, Quarts, Pounds etc.)
:lol: That's funny!! I'm American but can't help agreeing with you, seems we need to be different in everything! :rolleyes:
Looking at your figures, they look good, as far as I can tell, not being used to real numbers and all :D , I do have a question, you're collecting 27 ltrs, is that enough? do you top up? is that suficient to allow for evaporation? I ask because if you're making a 23 ltr batch, that allows 4 ltr for evaporation . (be patient with me, I need to learn real measurements, and I'm not trying to be a smart a..) ;)

steve_flack

Post by steve_flack » Tue Sep 05, 2006 3:45 pm

I thought evaporation should be about 10% per hour. So 4 litres should be about right. What struck me was the amount of grain seemed a bit large for a normal bitter or ale. I'd reckon on 4-5kg.

PieOPah

Post by PieOPah » Tue Sep 05, 2006 3:47 pm

These are figures I need to play around with. The size of my boiler will currently only allow for 27ish litres so I can always top up. The calculator will automatically adjust depending on your final boil amount

PieOPah

Post by PieOPah » Tue Sep 05, 2006 3:48 pm

QUOTE (steve_flack @ Sep 5 2006, 03:45 PM) I thought evaporation should be about 10% per hour. So 4 litres should be about right. What struck me was the amount of grain seemed a bit large for a normal bitter or ale. I'd reckon on 4-5kg.
Just a figure I had plugged in at the time. My normal bill will be around 5kg

Just realized that I had protected the sheet... This has been unprotected now so figures can be changed :D

PieOPah

Post by PieOPah » Tue Sep 05, 2006 3:56 pm

QUOTE (andy @ Sep 5 2006, 03:34 PM) Looks good....

A question though, why the "Top up Volume" addition ? Such a small quantity that it's not worth it is it ? Can't you just up the initial mash liquor quantity or the second sparge quantity to cover it ?)
That is because with a large amount of grain means a bigger initial run off. With a normal grain bill of about 5kg then this means you would need a top up of about 6 litres.

I don't know the science of the mash so I have taken the values I got from Denny Conn's site literaly. From what I understand, doing the mash with exact amounts gives you a better extraction. This means that if I was to add the top up water to the Mash from the begining then this would lower my extraction.

This might not be 100% true, but I'm just going on a method I have found :D

BitterTed

Post by BitterTed » Tue Sep 05, 2006 4:05 pm

QUOTE (steve_flack @ Sep 5 2006, 02:45 PM) I thought evaporation should be about 10% per hour. So 4 litres should be about right. What struck me was the amount of grain seemed a bit large for a normal bitter or ale. I'd reckon on 4-5kg.
Hmm, you say 10%, I guess I get a very aggressive boil, and have been told as much. I usually go with about 15% and that puts me in the ballpark .

Vossy1

Post by Vossy1 » Tue Sep 05, 2006 4:20 pm

Ditto BT, I calculated for 10% recently and overshot by quite a bit and had to redilute to volume. I think 10% is conservative ;)

steve_flack

Post by steve_flack » Tue Sep 05, 2006 4:26 pm

IIRC George Fix had a bit on evaporation rates in one of his books. Again IIRC, he said that if you decoction mashed a beer style that is normally infusion mashed (why you'd do this is another matter) you should aim at a low evaporation rate and a high evaporation rate if you infusion mash a normally decoction mashed style. Certainly a higher evaporation rate would perhaps indicate a great thermal load on the wort and perhaps increase caramelisation (which maybe is what Fix was alluding to in his books as the decoction process tends to increase caramelisation anyway)

steve_flack

Post by steve_flack » Tue Sep 05, 2006 4:31 pm

QUOTE (Vossy1 @ Sep 5 2006, 03:20 PM) Ditto BT, I calculated for 10% recently and overshot by quite a bit and had to redilute to volume. I think 10% is conservative ;)
I wasn't saying that people don't get higher evaporation rates (for the record,I used to when I used the burco) but maybe they aren't the optimum. I'd be happy with 10% and it's what I aim for. What does overboiling get you? You waste energy and maybe have to add water back to compensate for the liquid you've (quite expensively) boiled off?

bod

Post by bod » Tue Sep 05, 2006 5:00 pm

when i first started batch sparging, i just went with a basic rule of 4 gallons to start with in the tun, and 3 gallons to sparge with.
i lost roughly a gallon due to the dead space and grain absorbtion, so i collected 6 gallons in total from the tun, and after boiling, collected 5 gallons from the boiler, maybe less if using more hops. this was based on recipes containing 4.5 to 5 kg of grain.

run with your calculations for a few beers, because even if it looks right on paper, you can be sure something will affect it in reality! <_<

Vossy1

Post by Vossy1 » Tue Sep 05, 2006 5:20 pm

QUOTE I wasn't saying that people don't get higher evaporation rates (for the record,I used to when I used the burco) but maybe they aren't the optimum. I'd be happy with 10% and it's what I aim for. What does overboiling get you? You waste energy and maybe have to add water back to compensate for the liquid you've (quite expensively) boiled off?

Couldn't agree more ;)

Unfortunately for me, my boiler isn't thermostatically controlled, so what I get is, what I get. I can't dictate any percentage, though I would like to.
If I start to encounter the caramelisation then I will have to look into this further B)

eskimobob

Post by eskimobob » Wed Sep 06, 2006 11:14 am

Hi PoP,

I've taken the liberty of modifying your spreadsheet a bit to include evaporation during the boil. Hope you don't think I have taken too much of a liberty :ph34r:

I've removed the top-up bit and simply increased the sparge quantity although obviously you may not use the full quantity of sparge water if sparging is completed before you have used it all therefore in that case you would just transfer the remaining amount to the boiler.

Here's a http://www.berriman.co.uk/hobbies/brewi ... needed.xls.

Be interested in your thoughts...

PieOPah

Post by PieOPah » Wed Sep 06, 2006 11:25 am

If using an evaporation rate then it would be better to state the final volume of wort which would then give an amount needed for the boil.

so if I wanted 22.73 litres and a 90 minute boil then with 10% evap, how much wort would I need to boil?

Not quite sure how the formula for that would go....

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