Dead space !

[DC]

Hi all, I have just completed my AG setup and I have just measured the dead space in my mashtun and 10 gallon H&G bolier (see below) and ended up with 1.2L of water left in my cool box mashtun & 2.5L of water left in my 10 gallon H&G boiler I was just wondering if this the average amount of water left over in a mashtun & boiler and is there anything I can do to reduce the amount left in both the mashtun & boiler ? I have heard people mention the (syphon effect) but I am not sure what that is or how it works




Cheers DC

[simple one]

There is no real need to concern yourself with the dead space in the mash tun. The wort left in there will be watered down (esp if fly sparging) that it is a fraction of the wort sugars by volume.

Unfortuneatly as has been pointed out to me before. The Boilers dead space is the least of your worries. Once the hops are present too, the loss of volume is even greater. Most people quote 2-3 litres on average.

I once "sparged" the boiler after the run off, to try and eliminate dead space, and the absorbtion of hops. But its a fruitless exercise really. I just put it down to one of those things now. (it can be lessened by putting hops in muslin bags, but thats a whole different thread)

[OldSpeckledBadger]

I don't know what the average boiler dead space is but I've built a 25 litre boiler this morning and spent a lot of time fiddling to get the dead space down to about 1 litre. This was just testing it with water. In practice some of that space will taken up by the hops. So maybe your 2.5 litres in a 10 gallon boiler isn't that bad?

[hotmog]

Your theoretical dead space in the mash tun is probably only about 0.25 - 0.5 litres, and around 2 litres in the boiler including loss to hops & trub. The reason you're not achieving that is because you are losing the siphon effect once the level of wort drops below that of the pipe feeding the tap, because you're using a curved 15mm pipe coming out of it which is too large a diameter to sustain it for the rate of flow.

You need to constrict the outlet pipe from the tap to around 10mm - see this thread viewtopic.php?f=6&t=22423 - and you'll find you're not losing 2 -3 litres of perfectly good wort in every brew you do from now on.

[WishboneBrewery]

From my blog: http://pdtnc.wordpress.com/2009/04/26/s ... onversion/

The first drain down of the pot left about 1 Litre of liquid and I had to tilt the pan to get it to drain that far. I did some reading up at http://www.jimsbeerkit.co.uk and started looking into the ‘Syphon Effect’ and decided to stick some electrical tape over the top two thirds of the strainer (the bottom third of the holes are left open) holes and also reduced the internal diameter of the outflow pipe with a bit of PVC tube stuffed in the end. I did the same drain down test and found that it not only drained down faster but also only left 75ml of liquid in a level pan, no tilting necessary!
Now I just need to get a 15mm-10mm copper reducing fitting for the outflow pipe (which is about 400-500mm long) and solder up the top two thirds of the holes in the hop strainer. I’ll also drill some more holes in the remaining bottom third to as to keep a good open area.

Can’t wait for the next brew day now I can’t help but think that I could half cool the wort via the outflow pipe now too if I just did a bit more coper pipe bodging and turned it into a counter-flow chiller!

My modified hop Strainer section, holes just in the bottom third of the tube, makes use of the syphon Effect:

[Subsonic]

If you are really concerend about the deadspace and want to lose it - use marbles. They just take up the space that the liquid would have otherwise occupied and are inert. In practice we all live with some deadspace and after a while you get used to it in your recipes. Subsonic.

[Parva]

I'd be really concerned about using marbles due to them not being rated to boiling point and also the activity within the boil itself, shards of glass in my beer aren't something I would fancy trying.

[DC]

Hi all, After reading the posts suggested by pdtnc & hotmog, I have fashioned an addition to my 15mm copper pipe that comes from my mashtun and boiler (see below). I had the volumes listed below, these volumes were reduced by a hell of a lot all by just reducing the diameter of the outlet pipe. I am hoping that this information I have supplied might go some way to help other members who are thinking of building an AG setup.

BEFORE 15MM COPPER PIPE MODIFICATION

MASHTUN: 1150ml water left in dead space
BOILER: 2500ml water left in dead space

AFTER 15MM COPPER PIPE MODIFICATION

MASHTUN: 350ml water left in dead space
BOILER: 700ml water left in dead space




Cheers DC

[WishboneBrewery]

Good stuff

[OldAl]

Just to put in my ha'porth worth:-
When I made my coolbox mashtun, I realised that using the syphon effect, the tap didn't have to be at the lowest possible level, so there was no need for convoluted bendy pipes to fit the manifold to the tap.
I made a neat manifold first & cut the tap hole to line up with the manifold, rather than the other way round. It works well in practise. Tested with water, the dead space was < 150 ml. That really surprised me.

mashtun manifold.JPG (33.97 KiB) Viewed 3008 times

If you don't want to use marbles in your boiler to reduce deadspace, SWMBO suggested using these. They look a lot safer than marbles but I haven't actually use them myself. Has anyone else used them?

[hotmog]

If you don't want to use marbles in your boiler to reduce deadspace, SWMBO suggested using these. They look a lot safer than marbles but I haven't actually use them myself. Has anyone else used them?

Don't see why they shouldn't work, but you'd probably need at least 3 or 4 of those 700g pots to fill the required volume, which starts to work out quite expensive. Then there's the messy business of trying to separate them out from the spent hops and trub sludge afterwards, and washing them ready for use next time.

[OldAl]

Don't see why they shouldn't work, but you'd probably need at least 3 or 4 of those 700g pots to fill the required volume, which starts to work out quite expensive. Then there's the messy business of trying to separate them out from the spent hops and trub sludge afterwards, and washing them ready for use next time.

Yeah. Just pointing out a safer alternative to marbles. Personally I don't see much point in using them unless you can't reduce a big deadspace any other way. Just wondering if others had used them & how they did it. Although expensive, they would last ages and you could enclose them in a muslin bag or sock (a clean muslin sock that is, not a typical brewer's sock ).