Batch Sparge Question - Grain to Water Ratio vs. Equal Run Off's?

[Jiffster]

I've only got 5 AG batches under my belt so not enough experimentations to know this for myself yet.

I've read and used 2 methods:

1) Mash at desired grain/water ratio (i.e. 1.25 qt/lb), collect run off and measure to determine spare volume need to collect boil volume.

2) Mash at desired grain/water ratio (i.e. 1.25 qt/lb), after mash add additional water to bring up to pre-calculated volume that would yield 1/2 of required boil volume (i.e. lets say 1 gal), stir in and let sit a few minutes, collect run off (which should equal half required boil volume), batch spare with volume that should be equal to half required boil volume.

Is there any benefit to method 2 over method 1?

 

[brewkinger]

Not that I can think of

 

[kh54s10]

No benefit that I can think of either.

I do my mash with the volume wanted by Beersmith. I set the ratio somewhere in the setup. Then I drain and measure what I need for sparge. I add somewhere over 1/2 needed to get to preboil, measure again and then do a second sparge with what I need to reach my preboil volume. I do this so I am sure I will get enough wort and also not leave a bunch in the mash tun.

I just feel it is easier this way.

I have gone with the amount that Beersmith asks for the sparge and it didn't match what I needed for preboil. It was close though. I have also tried a single sparge and came up just a bit short for preboil so I had to add some more water anyway. Another time I was left with a little extra in the tun. The worst part of that is it made the tun heavier to carry to my compost pile.

 

[IslandLizard]

1. is better since you'll have more sparge water left.

1. Collect first runnings
2. Add half your sparge water (amount is not very critical), stir well, collect
3. Add the remainder your sparge water, stir well, collect

Use a mash calculator like Brew365.com to calculate the total amount of water needed. The only thing I change is my strike water needs to be 5°F higher to combat heat loss while stirring the mash initially. I then cover the mash with a double layer of aluminium foil and close the lid. I may check after 20'.

 

[Jiffster]

Thanks folks!

 

[doug293cz]

If you want to stick with a single batch sparge, then the best method is to forget about a specific mash thickness, and just mash with enough water to get half your pre-boil volume from your initial runnings, and then sparge with the other half of the pre-boil volume. This will give you a mash thinner than 1.25 qt/lb (except for the largest grain bills.) The thinner mash will help your conversion rate, which may improve your conversion efficiency depending on mash time (ref: http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Mash_thickness.)

In the above case:

Sparge Vol = Pre-Boil Vol / 2
Strike Vol = Sparge Vol + MLT Undrainable Vol + Grain Wt * Grain Absorption Rate​

If you want to be really accurate, then compensate all volumes for thermal expansion (i.e. adjust all volumes to the same reference temperature.)

If you want to do two sparges, then you can calculate sparge volume with the same formula as above, but just use a 3 in the denominator rather than a 2. For grain bills of about 12 lb or higher (for a 5 gal batch) this will result in mash thicknesses of less than 1.25 qt/lb, in which case you probably want to up your strike water to give 1.25 qt/lb. Then you recalculate sparge volume as:

Sparge Vol = (Strike Vol - (MLT Undrainable Vol + Grain Wt * Grain Absorption Rate)) / 2​

for each of the two sparges. Or, if you are comfortable with the ad hoc methods suggested by previous posters, there's nothing wrong with using those methods. It depends on whether you're more comfortable planning or reacting. (Personally, I like to plan, and then be prepared to react based on anything unexpected.)

Brew on

 

[dmtaylor]

Is there any benefit to method 2 over method 1?

Method 2 maximizes efficiency and that's why I do it. If/when I don't care about efficiency (sometimes I don't), then I don't sparge at all.

 

[doug293cz]

Method 2 maximizes efficiency and that's why I do it. If/when I don't care about efficiency (sometimes I don't), then I don't sparge at all.

It is the equal runnings volume that maximizes lauter efficiency (ref: http://braukaiser.com/wiki/index.php?title=Batch_Sparging_Analysis.) There is no benefit to limiting mash thickness to 1.25 qt/lb, and then adding water prior to initial run off. Add all the volume needed to get your first runnings as strike water. If you are having conversion efficiency issues, then having a thinner mash will actually help you (ref in previous post by me.)

Brew on

 

[dmtaylor]

It is the equal runnings volume that maximizes lauter efficiency (ref: http://braukaiser.com/wiki/index.php?title=Batch_Sparging_Analysis.) There is no benefit to limiting mash thickness to 1.25 qt/lb, and then adding water prior to initial run off. Add all the volume needed to get your first runnings as strike water. If you are having conversion efficiency issues, then having a thinner mash will actually help you (ref in previous post by me.)

Brew on

Good point. Personally I don't need any help as this is what I typically do anyways. Ratio really doesn't matter, I agree. Typically it is somewhere in the neighborhood of 1.5 to 1.75 qt/lb but it doesn't matter. What matters is equal runnings. Yes. I've gone up to average 90% efficiency and back down again to low 80s by choice. Today I got 76% efficiency on a 1.077 beer. Could have been higher if I cranked down more on the mill gap, but I choose not to do that. Oh, and I only mashed for 30 minutes as a bit of an experiment.