working out brew length including dead space

[Newtons Shed]

Hi all I am very nearly up and running again, just awaiting a pump from ebay. Last night I spent the evening marking off the water level on the cheap sight tube I've put on the HLT and this holds 50L I also have same size MT and boiler, the system also has a domestic kettle as a herms . What sort of brew lenght should I aim for? Obviously most recipes are based on 25L and will need scaling up but I don't know what to scale up to as don't know how to work out the maximum I'd be able to get out of it?
I started to work out any dead space by tipping the HLT forward once nearly drained, I have about 1/2l to 200ml dead space ie water I couldn't get out, I'm not sure if the pump would drain this better? As the bottom tap in all three tanks are in the same position, would this mean there be this same amount of dead space in each of the 3 pots or will it be different once grains and hops and manifolds are taken into account? As the grain would absorb some of the liquid and likewise some will evapourate in the boil, I guess this all needs calculating and adding to the losses before I know the brew lenght right, or is there a way to predict and compare back to the actual?

IE if doing a 5% bitter mashing at 2:1 ratio how much water is needed, how much grain and how much beer would be made? Assuming 10% boiled off and 1/2L dead space?
Thanks all for any help I just can't work out what calculation need to be done and what fixed know's I need to know to calculate the missing parts and what the starting point to calibrate my new setup
Thanks again

 

[Vossy1]

How I calibrated my HLT...it has a elbow on the rear of the tap as close as possible to the floor of the vessel. Fill vessel above tap level, open tap, when the flow stops close tap. Now start adding in litre increments to calibrate you volume. don't be tempted to tilt forwards...it's jut too much messing about and how can you ensure you do it to the same amount each time.

Add the dead space to the volume of mash liquor you want/need.
I can't remember the grain absorption ratio of the top of my head at the mo
IIRC it's 5mm/ltr in your pot, or is that mine :wha: so I wouldn't want to go much over 40ltr boil volume in your copper, which could be 5cm from the top...double check :thumb:

 

[Newtons Shed]

Thanks Vossey.

Wasn't sure which way to do this, ie mark water level off without taking account any dead space then work out the dead space and add this to the volume transfered from hlt to mt each time or like you've done start marking up from the dead space, as I wasn't sure how much would be left in the HLT taking into account any suction gained from pumping? I just jugged water in a liter at a time and marked off on the sight tube as I went, then I worked backwards by emptying liter out at a time from 10 liters and got 8 liters out so I know 2 liters left in then tipped forwarded and giot another 1.5l out tajke your point that if tipping may be different each time.

Just done a quick google search for grain absorbtion rate, american home brew forum has (lbs of Grain) x 0.20) = Absorption loss in gallons. Converted to kg/liters 1kg = 2.20462 lb x0.2 = 0.440924 US gallons = 1.67l so just under 2l for every Kg of grain used? So 5kg of grain absorbs just over 8 liters (1.67X5) does this sound about right? Would you take this into account when following say GW receipe books or has this already been taken into consideration?

Mash Water = Mash Ratio x Lbs Grain
say 2.5l:1kg ratio used X 5kg = 12.5 liters of liqour, 8 liters of which would be absorbed into the grain leaving 4.5 liters free wort right? Or would you add the 8L to the 12.5L giving a mash liqour of 20.5l? so say I wanted 40 liters in the boiler at 2.5l:1kg would that mean I would need 15kg of grist with 37.5liters of liqour and 25l (1.67X15) absorb into the grain giving 12.5l wort plus sparge? Souinds too high grain bill to me? I'm truely confused :wha:
What fixed constants do I need to knopw for my set up ? I know I need;
Dead spaces
Efficency
evapouration/boil losses should be around 10% ish?

 

[Good Ed]

Don't try and make things too complicated, and also it's only by brewing that you will get used to your system, and this will take several brews to refine. You will also need some brewing software for your recipe, I use BrewMate, free and easy to use, you will have to estimate an efficiency, use 73% to start with, and don't get hung up on efficiencies as it's just a number in your recipe that works for you, again you can adjust it over time.

I brew 23L brew lengths with a plastic bucket at electric element. So generally for the mash I use 2.5L/kg with no allowance for grain absorption; you then sparge this, and I fly sparge so I don't know about batch sparging, with the condition that you don't spage any more liquor below SG 1008 (true) due to possible tannin extraction; but this is when you have to decide what your pre boil volume should be; now for my set up I use, brew length + dead space of boiler + loss due to displacement and absorption of hops = 1.6L/100g of hops + loss to evaporation, my set up is about 9%/hour + I allow 1L for the volume decreasing from 100c to 20C.

Hope this helps