What Size Mashtun?

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Today I did my first AG brew and my 26 litre esky mashtun was pretty close to full.

Its a pretty old esky and I found out that it leaks from where the handles are attached although not so much that is was pissing over the floor.

The long and the short of it is - I need to buy a new esky - what size do people recommend?

I am curently doing ~23 litre batches with no immediate plans to go bigger.

The pic is after draining quite a bit, it got to about an inch from the top.

I'm aiming for around the 40lt mark
I had 7kg of grain in mine with 21 litres of mash water last weekend.
I then batch sparge and would have initially added another 10 litres or so for the first runnings. That had it pretty full so I estimate mine to be around the 40 litre mark.
It is a good size.

Just so I get this straight (I am new to this):

7 kg grain
21 litre mash water
+ another 10 litres before you start draining.
So given that the grain absorbs say 7 litres you get around 24 litres out.

Then you batch sparge with 21 litres so you end up with around 45 litres of wort?

What batch size are you aiming for? I am only aiming for around 23 litres.

What the grain absorbs you never get back.
eg. When you have drained the tun the grain is still holding its weight in liquid.
I collect 33 litres to end up with 23.4 + dead space at the end of the boil.

So the grain takes up space in the tun and absorbs its weight in water 1.01 litres/kg. Then add in extra mash water. I don't drain the tun at the end of the mash straight away. Some brewers do some don't. I fill it up to the top then start draining.

The 7kg or so soaked up by the grain is not the problem - my assumption of your sparge volume was out of whack.

21 litres mash + 10 litres added at end of mash
=> 31 litres so far
less 7 due to absorption
=> 24 litres
So I take it you sparge with 10 litres to take it to around
=> 34 litres collected

And after boiling, cooling etc you get around 23 litres.

I have been trying to work out my volumes so I collect 1/2 from mash and 1/2 from sparge, for no other reason that John Palmer and various others recommend this (without really saying why).

So if my grain bill used 7kg grain and I wanted to collect 34 litres:
mash with 34/2 + 7 = 24 (I would probably add the extra 7 near the end of mash)
sparge with 34/2 = 17
24 + 17 - 7 = 34.

Which would overflow my 26 litre esky both times.

Anyway, like I said this is new for me so I just would like some confidence that my calculations aren't totally screwed.

Oh yes and the Wit is bubbling away nicely.
Maybe this will explain it better.

21 litres of water for the mash. The grains abosorb 7 leaving a result of 14 to get from the mash.
Then sparge with 19 to collect 33 litres of wort.
After boil down and allowing for dead space in my boiler I'm left with 23.4 litres.

Here is the promash calcs which work exactly for my system.


Edit: So based on your system you would have to fly sparge unless you wanted to batch sparge like 3-4 times.

Bunnings has a couple of different brands too. I haven't compared the prices but the ones I have seen in aussie disposals seem to be high end products (and priced accordingly).
Rays outdoor has 42 litre coolers for $62 at the mo - their marked price is $89. They even chuck in two other little coolers (which I could do without). This is competitive with the bunnings prices on the local brands.

The nice thing about the rubber made is that the drain looks like can be removed without too much trouble. OTOH when you open them up they stink pretty bad. I assume a good wash and air would solve this.

Oh yes and as an aside, Grangers camping (up the road from Rays in Nunawading) had the 3 ring LPG burners for $36. That's much lower than I have seen them elsewhere.

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