Dilution percentage

pms67 · Jan 17, 2017

Apologies if this is daft,it usually is.
Lets say i brew 16 litres and og is 1054,how much water would be required to bring it to 1046? Is there a calc per litre, if the ingredients are for a 20l brew i dont want to top it up with 4 litres and end up overdiluting it.
Cheers

IainM · Jan 17, 2017

The product of gravity units and volume stays constant, so 16*54 = x * 46, solve for x to get the total volume you want: x=16*54/46 = 18.8L, so you need to add 18.8 - 16 = 2.8L.

dad_of_jon · Jan 17, 2017

pms67 said:
Apologies if this is daft,it usually is.
Lets say i brew 16 litres and og is 1054,how much water would be required to bring it to 1046? Is there a calc per litre, if the ingredients are for a 20l brew i dont want to top it up with 4 litres and end up overdiluting it.
Cheers

I think you could extrapolate it so 16l at 1054 and 16l water (which is 1000) = 50/50 mix

50% of 1054 + 50% of 1000 = 527 + 500 = 1027. the calculation would be on the ratio. 1:1

16 litres and you want 20 = 16 litres to 4 = 4:1 = 5 parts therefore 4/5 of 1054 + 1/5 of 1000 = 843.2 + 200 = 1043.2

16 litres + 2 litres = 18 = 8:1 = 9 parts or 8/9 of 1054 plus 1/9 of 1000 = 936.88 + 111.11 = 1047.99

so 16 litres + 2.4 litres = 6.666:1 = 7.666 parts = 6.666/7.666 of 1054 plus 1/7.666 of 1000 = 916.509+130.446 = 1046.95

or *****************************************************

This is from one of Aleman's posts on how to liquor back

(Current Gravity x Current Volume) / Desired Gravity = Final Volume

Just use the last 2 digits of the SG, ie 1048=48 and final volume will give you how much to add to the wort you have ended up with

eg (54x16)/46 = 18.78 liters - 16 litres original therefore at 2.78 litres

dad_of_jon · Jan 17, 2017

IainM said:
The product of gravity units and volume stays constant, so 16*54 = x * 46, solve for x to get the total volume you want: x=16*54/46 = 18.8L, so you need to add 18.8 - 16 = 2.8L.

trust me to go the long way about it

IainM · Jan 17, 2017

dad_of_jon said:
trust me to go the long way about it

At least we got the same answer!

MyQul · Jan 17, 2017

I have no idea what the other two are on about as I'm so cack at maths...so I just use a dilution calculator for this kind of thing

http://www.brewersfriend.com/dilution-and-boiloff-gravity-calculator/

johnnyboy1965 · Jan 19, 2017

pms67 said:
Apologies if this is daft,it usually is.
Lets say i brew 16 litres and og is 1054,how much water would be required to bring it to 1046? Is there a calc per litre, if the ingredients are for a 20l brew i dont want to top it up with 4 litres and end up overdiluting it.
Cheers

Erm...pour some water in, test it,pour some water in, test it, pour some water in, test it

pms67 · Jan 19, 2017

johnnyboy1965 said:
Erm...pour some water in, test it,pour some water in, test it, pour some water in, test it

That sounds a hassle,I'm too lazy,just wondered if someone knew,which they did :thumb:

Dilution percentage

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