Batch Sparging

[mctoon]

Just a quick question,

how long ish does is take you to drain after adding the first sparge water?,

Reason im asking is i have used my new mash tun and i have had 2 stick!!!!,, i think i may be draining too quick

Cheers Mal

[DarloDave]

Is the water supposed to be completely drained? Mine normally stops draining when there is still a bit of water left, is this stuck, or is this normal? I think this is also the reason I seem to end up with a few litres less in the FV aswell.

[derekp]

I have just set up a picnic cooler as a mash tun and put water in it then drained it, there was still 1.5 ltrs of water left in the box

[DarloDave]

ah that is the reason im not hitting my targets then, im guessing it's alright to give it a little stir to try and get a bit more water drained out. cheers Chris.

[hotmog]

Is the water supposed to be completely drained? Mine normally stops draining when there is still a bit of water left, is this stuck, or is this normal? I think this is also the reason I seem to end up with a few litres less in the FV aswell.

All visible liquid should drain from the tun.

Like Chris said, all visible liquid should drain out to the level of the outlet pipe opening.

This does, however, rely on the siphon effect being maintained. This means that:

a) the bottom opening of the tap must not be higher than the opening of outlet feeder pipe, and

b) the rate of flow relative to the diameter of the tap outlet pipe must be sufficient to keep the pipe full of liquid while the tap is turned on to prevent air entering.

My mash tun and boiler originally had taps like this, with a bit of tubing fitted on the end:



I never had a problem draining the very last dregs from the false bottom in my mash tun, or from my home-made hop strainer manifold in the boiler, using these taps. However, like a lot of people here seem to have done, I recently replaced those taps with 15mm lever ball valves, which feed out through a 15mm copper pipe with a 90 deg elbow. I noticed that my last brew didn't seem to drain completely from the boiler into the FV, and I ended up having to top up with 1 litre of water to make it up to 23 litres. When I tested it afterwards by filling it with water above the level of the tap and then opening it, my suspicions were confirmed. As the level of water reduced, so did the rate of flow to the extent that it became a fast trickle that stopped altogether once the level of the water reached the level of the tap (which is slightly higher than the hop strainer manifold). The amount of water remaining was about 2 litres more than would have been drained with the old taps.

I realised the problem is that the rate of flow through the wider 15mm pipe is not sufficient to fill the pipe when the water level/pressure in the boiler reduces, allowing air to enter the pipe and destroying the siphon effect. What I needed to do was to constrict the outlet pipe to a similar diameter to that of the old taps. I soldered a bit of 10mm copper pipe left over from my home-made wort chiller on the the end of the 15mm pipe, like this, and tried it out:



Voila, problem solved! It works perfectly - all the liquid now drains out. It will save me 2 litres of lost wort every brew, and could well do the same for many of you too.

[mctoon]

Generally with batch sparging you can run off as quick as the tap will allow. If you are getting a stuck mash i'd look at the design of the mash screen and consider increasing the drainage area (ie drilling more holes or cutting new slots).

More holes it is then...... Cheers Chris

[WishboneBrewery]

This sounds interesting...
Smaller tube to keep the syphon effect going