SoMe one sort the mess I've made out

[sbond10]

Agh can some sort of the mess I currently made of my measurements out

I have a 98 litre pan 50x50 cm
I started with 43 litres of water in the pan
I put the grains in and a headspace of 21cm
After mash I had 17cm headspace
After the boil and cool down I ended up with 29 litres...

Is someone able to make heads and tales of this mumbo jumbo of numbers shit I can already see an issue please someone try n work out what I've managed to do

Cheers sean

[Mr. Dripping]

You need to calculate how much liquor the grains have absorbed and the amount lost to boil off.
IIRC, BIAB works on 0.7-0.8 litres absorbed per kilo of grain used.
Your boil off will depend on quite a few factors....best determined empirically, but will be between 10 and 15% per hour.

You will also lose an amount to trub being left after the boil.

Edit - how much wort were you planning to make and did you hit your OG target??

[sbond10]

I was aiming for 23 litres so I over shot by 6 litres the planned gravity was 1.041 but I got 1.036 so I can say I lost between the boil off and mash I lost 14 litres of water. I had a total grain of 4.2 kg so judging by your calculations I lost about 3.6 litres of water so that means 10.4 litres dissappeared to evaporation and hops

[Mr. Dripping]

I've just run those number through BrewMath.......your efficiency is actually quite good. If your target was 23@1041, dilution to 29 litres should give an OG of 1033, so you are a few points up on gravity.

[sbond10]

Oh yea I got 1.028 at 64 degrees after mash/before boil and the 1.036 was taken at 26 degrees

[vacant]

For my BIAB I start with around 34L in the boiler for a 23L brew length.

If I understand this correctly: 21cm head space with bag, 17cm after bag of soaking grain removed?

25 x 25 x pi x (25 - 17) = 7854 i.e. the bag of grain plus water had a volume of 7.854 litres - about right, grain is less dense than water. probably around 3 litre of water in that bag.

Leaving 40 litres.

If 2 litres are left in the hops/trub then 40 - 2 - 29 = 9 litres boiled off.

I boil off 8 litres/hour with two Asda kettle elements, 3.6 litres/hour with one

[sbond10]

So I'm guessing I did pretty well for a first all grain brew despite me messing up my figures so if I drop my water to 38 litres next time around ill be using 6kg of grain I should be closer to my mark?

[Manngold]

I think so Sbond. It is all trial and ever, even after 9 BIAB I am still getting all my measurements in line. I have found that 35 - 37 (dependingon the amount of grains) works well.