Batch Sparge Mash Question

[calumrobertson]

Hi,
Have done a few AG brews now and al going fine. However im not 100% sure if im doing the batch sparge completely correct...
Ive got a cool box mash tun, i start off by doing a 90 minute mash at 68c with the water:grain ratio of 2.5:1. Then once 90 mins is up i top it up with the volume require to give me run off of 1/2 the final volume required for the boiler with water at 85C and drain until the grain is dry. I then at a final volume of water at 85C (equal to 1/2 the volume required for the boiler) and again run dry. Is this correct.
The reason i ask is i have a 30l cool box but if im doing sort of 5.3+kg grain bills by the time ive topped up the first time its pretty much overflowing....after the 90 minutes is up should i drain the mash tun without adding more water, then sparge twice?
Cheers

[Rick_UK]

Hi Calum

I'm pretty new to AG brewing and have only just completed by first brew, but I did use the batch sparge method with my 24l cool box mash tun, and I did plenty of research beforehand.

My understanding is that you can sparge in 2 or more rounds without any issues. Some brewers argue that splitting it into 2 rather than one big one is better but I think this is anecdotal. I used the following procedure without any issues:

1 - Workout total liquor required, adjusting for grain absorbtion and evaporation (I think there are calculators you can use for this on t'internet)
2 - Mash with specified mash liquor and collect first runnings
3 - Refill MT with half of remaining water at 80 deg C, stir and leave for 20 - 30 minutes, drain off
4 - Repeat 3 with remaining liquor and collect final runnings (by this stage the liquor was nearly clear)

So in short - Yes! (At least in my limited opinion).

Rick

[Kev888]

Calum,
It sounds like you're doing it in the normal manner, and I'd expect a 30L MT would indeed max out in two batches at less than 6kg grain bill. If limitations of equipment mean you need more smaller batches then thats common too - just more work (in some cases it may make more sense to fly sparge than have more small batches).

Aleman's recently updated batch sparge calculator now includes the required mash tun capacities in the results, so that'll help you see what is what.


Cheers
Kev

[calumrobertson]

Thanks, i was sure i was doing it the right way since i'd read up on it beforehand and has been giving decent results since...just when it was almost overflowing i was thinking 'is this right'?! Guess that means if i want to make stronger beers with bigger grain bills im just going to have to do it in multiple sparges with the equipment i have.
cheers

[Kev888]

Yeah that sounds about right. In theory you should be able to mash up to around 8kg or more grain-bill in your MT at the stiffness you want, but you'd either have to batch sparge with smaller and so more sparge volumes (I would have thought three, but haven't worked it out) or fly sparge.

Personally I find batch sparging becomes a bit tedious with full tuns and more than a couple of batches and so always fly sparge when they get full, but thats simply my choice.

BTW one other possible influence is that a nominal '30L cool box' may be a bit misleading - some count space in the lid, which is not actually useable for liquid.

Cheers
kev

[flytact]

I concur with the above. I often calculate my 3nd and 3rd additions based on draining the initial mash.
I would recommend a 60 minute mash. I don't think you're getting anything out of that extra 30 min. Sometimes my mash is complete in about 45 min.