Mash water volume? vs sparge method ?

The Homebrew Forum

Help Support The Homebrew Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


New Member
Mar 17, 2023
Reaction score
Dorset UK
I have some questions about sparging. Depending on which item you read how do you determine the % of water for the initial mash ?.

I am using the 'in the bag' method but thought to vary the sparge method a bit.

The first mash I figured to use half (50% of total) the total volume of water. Then transfer the bags to a bowl of water (25% of total) around 65-70C for about 10 mins or so, transfer the extracted liquid to the original mash, then repeat with the remainder of the liquid.

By doing it this way the bag(s)* would be immersed in liquid ( and squidged ) for the 'sparge' part hopefully increasing the extraction. The only additional equipment needed is a clean washing up bowl and some hot water. And the wort remains in the boiler ready to boil.

Can anyone see any reason this would not work ?
Would the extraction rate be comparable to traditional sparging methods ?

Thanks for your interest.

Best Regards


* I use 3 or 4 muslin bags for ease of handling. The bags have tie strings at the top to close them and make it easy for removal. Even considered using a lidl shopping bag. They do two varieties, jute and cotton.
I use 2.7 litres of water to each kg of grain for the mash (plus extra to allow for the dead space in mash tun if applicable), then the remainder for the sparge.

Your method effectively has two equal dunk sparges, which in theory would be more efficient than one, but is it worth the extra hastle for the minimal extra extract? Also it may run the risk of tannin extraction if the SG of the sparge falls to low (below 1.008). Sparges are normally carried out at 75°C, lower temps will take longer to dissolve the sugars off the grains, temperatures of 80+°C will draw astringent tannins into the wort.
Where do you derive the 2.7L per kilo from ? Its pretty close to the 50% I was considering (amazing - worked it out to 2.666 -- that's really close, 50% of 24L / 4.5Kilos)). I was just guestimating it.

@ Caramel Ox
My Boiler holds over 30L. Its an old tea urn rescued and repaired from a car boot.

@ Tanglefoot
Would love to try that for less hassle. How much grain increase is needed ? . I assume the mash temperature and time is the same ?
Tried researching it on this forum using spargeless as a search term, then sparge which returned zillions of not relevant results :-(.
As an aside I ought to rename myself as Old Thumper - Sadly the Old Thumper nowadays is unrecognisable from the original in terms of flavour. I think the original recipe was sold to an american brewery. It was the beer that started my beer interest .. .

Best Regards

I used to use BrewMate and that calculated the mash and sparge volumes. I assume the maths is relatively easy - graiin X N for mash and the rest is sparge. I used to sparge by suspending the bag using a pulley system, lifting it to one side, pour over some sparge water and squeeze it until nothing more comes out and then repeat. Never occurred to me to use multiple smaller bags.

I would think that pouring through rather than dunking would be more efficient but it’s probably six of one…
Where do you derive the 2.7L per kilo from ? Its pretty close to the 50% I was considering (amazing - worked it out to 2.666 -- that's really close, 50% of 24L / 4.5Kilos)). I was just guestimating it.
I cheated, I use a Grainfather and its brewing software calculates all mashes based upon 2.7 l/kg. Different brewers use different ratios, but 2.7 is a good place to start from.
I'm not saying this is the right way, it's time consuming, but works for me & I'm happy to mess about doing this for an hour. (If you don't have the spare time do what @Caramel Ox suggests)

I generally do a jug sparge BIAB with similar equipment to you.
I have a perforated false bottom in my boiler that the bag of malt sits on.
So, wort from first mash is run off into a plastic FV with litres marked on it, so I can see how much I have.
Close tap.
Then, I start boiling 2/3 full kitchen kettle. Once boiled I'll top it up & pour it slowly onto the malt via top of the boiler.
Open tap & collect in a 2l plastic jug.
While jug is filling, put next 2/3 full kettle on the boil
Close tap & pour jug back through - so you use the hot sparge water twice.
Open tap & drain into FV.
You should have another kettle of boiling water ready to top up with cold & repeat until the FV reaches your desired volume. I generally use my final volume here as the dead space wort left in the boiler will cover my boil off volume.
Now, remove the grain bag & transfer the wort back into the boiler (I do this with the jug, the lift & pour in the last 8 or so litres)
Now you can boil.

I also leave the false bottom in for the boil as I use real leaf hops loose & it helps to keep them away from the tap.
I used to put the hops in a bag, but found hop pellets were just ground too fine to stay in the bag & when I used leaf hops I wasn't getting enough circulation & ended up using 50% more hops to get the desired flavours.
I believe the theory around how much water to use is concerned with the concentration of enzymes in the mash responsible for converting the starches into sugars. Modern grain though is well modified and this really shouldn’t be an issue for you (I’ve seen people do full-volume mashes with no sparge and I’ve seen very sticky decoction mashes - all good).

On a practical level the mash volume is probably linked to the volume of your mash vessel and the volume of grain - I use enough mash water to just cover the grain. If my intended batch of beer is bigger, the rest of the water goes to the sparge.

I’ve tried almost every way of sparging and while sparging (over not sparging) makes a big difference to efficiency the method of sparging is less dramatic. Your approach of dunking the spent grain bags in water is called batch sparging and is absolutely fine.

Other methods include putting the spent grain bags on an oven grill over a bucket and jugging water through the grain, or some (usually mechanical) process where water is sprinkled over the grain or dribbled through a perforated sheet. The slower more complex methods make small gains but for more time, effort, and cleaning up!

Latest posts