Efficiency Help Me I'm Confused (See lastest post)

[rimski]

Hi All

I would like to know what my Mash efficiency and boil details are from the following recipe and brewday

The mash section

Maris Otter Malt - 3.220 kg
Pale Crystal Malt - 0.170 kg

11.7 litres of strike water and 20 litres of sparging water total of 31.7 litres giving me a wort amount of 26 litres @ 1.038 OG before boil and 17 litres at 1.043 OG after boil

The Boil Section

As you can see from the above numbers I had 26 litres before boil and after a 90 minute boil I had 17 litres, I added

40g Challenger @ 90mins
20g East Kent Goldings @ 15 mins
20g East Kent Goldings @ Flameout
10g Bobek @ Flameout

How do I work out, without programs, what my hop loss and boil losses are.

If anyone could post the equations that would be even better so then I can work out all my efficiencies for future recipes

Cheers

Neil

[jubby]

Your boil losses are the pre boil volume minus the post boil volume in the boiler. Your hop & trub losses (including your boilers unusable space) are what you transfer to the FV. Hope that helps.

[Blackjack]

Hop utilisation is a black art not a science, but the formulae for estimating are page 22 of the latest edition of Graham Wheelers Brew Your Own British Real Ale. Basically multiply the weight of each hop that gets 90 mins boil by its alpha acid percent and add the different ones together, divide by the final volume and multiply by a fudge factor. Add a bit for those that get 15mins but ignore the post boil, finally see what it tastes like.

The figures are only of a little comparative use, hop tastes are different, they lose alpha when stored, the yeast affects the perceived bitterness etc etc.
50 or 60 grams of hops with alphas of approx 5 to 6% boiled for 90 mins in a 5 gallon brew will give a bitterness of approx 30 to 35 IBU's according to GW beer engine. use that as a benchmark