Promash Reports And Sparge Amounts

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I admit I'm quite new to AG brewing, but I'm trying to follow the recipe from a promash report to make a foreign stout.

The mash water amount is clearly noted down, but not the sparge amount?

This is the recipe:
(I'm making a ten litre batch)

Also, is 45 minutes necessary to batch sparging? I thought it was closer to 15.


The Imperial Metric Brewery
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Slight, you can work out your sparge water based on you target volume and system evapouration.

Lets say you are doing a 10L batch with the same recipe (half the grain of course) you will have roughly 3.5kg of grain and 9L of strike water. The grain will absorb roughly 1L/kg so of the 9L you use to mash only 5.5L will be recovered.

Let us now say that you expect to lose 2L to crud in the botton of the kettle & you will evapourate 2L per hour during the boil (so 3L for 90mins).

This being the case to get 10L in your fermenter you need 10 + 2 + 3 = 15L in your kettle.

You can only get 5.5L from the mash which means you need 9.5L of sparge water. When you do you calcs in promash your batch size is your post boil size (12L), you then lose 2L to trub in the kettle etc.

This is the general way you work out how much water, I am not a batch sparger but I assume you would add say 2L stir and then drain and then add the remaining sparge water so you get two rinses.

Hope that helps.