[Kaiser]

This is also the method that Kai describes in his article showing increased efficiency from equal size sparges.

In this article I'm talking about run-offs. The first comes from the mash and the 2nd comes from the 1st and possibly only sparge.

Kai

[dean]

Kai, what if you added your first sparge say 10 minutes before taking any runnings, would it have the same effect as a single batch no-sparge with a severe hit in efficiency?

[denny]

2 equal runoffs (1 drain, sparge, drain again) is how most everyone performs a batch sparge.

I thought the common method, and the one I use, is to mash in at your preferred grain to grist ratio, nominally 1.3 qts per pound.  After draining, you do two equal size sparges (letting each rest ~15 minutes while stirring occasionally) to collect the rest of your wort. This is also the method that Kai describes in his article showing increased efficiency from equal size sparges.

Brian

I almost never do more than a single sparge.  I get so little gain in efficiency form doing more that it isn't worth my time or effort.

[denny]

I have never waiting 15 minutes between sparges after stiring. Are you expecting more conversion to occur? I just stir, vourlat and drain and repeat.

There's nothing to be gained from waiting.  I do what you do.

[denny]

Kai, what if you added your first sparge say 10 minutes before taking any runnings, would it have the same effect as a single batch no-sparge with a severe hit in efficiency?

I'm not Kai, but yes...

[The Rabid Brewer]

I think the rationale for waiting a period of time after stirring is to allow sugar diffusion...

That was my understanding as well (I think I read it in Palmer) but I haven't done a lot of experimentation.

Brian

[denny]

I think the rationale for waiting a period of time after stirring is to allow sugar diffusion...

That was my understanding as well (I think I read it in Palmer) but I haven't done a lot of experimentation.

Brian

I've done a lot of experimentation on it.  No difference.

[bonjour]

I think the rationale for waiting a period of time after stirring is to allow sugar diffusion...

That was my understanding as well (I think I read it in Palmer) but I haven't done a lot of experimentation.

Brian

I've done a lot of experimentation on it.  No difference.

That is the logic, but the proof is in the brewing.

Fred

[Kaiser]

I think the rationale for waiting a period of time after stirring is to allow sugar diffusion...

That was my understanding as well (I think I read it in Palmer) but I haven't done a lot of experimentation.

I think the effects of that diffusion are commonly overstated. Throughout the mash the sugars dissolve into the wort which can be measured by the mash gravity test. Once you are close to 100% conversion efficiency there can't be a significant amount of sugars in the grains or husks or otherwise the mash gravity would be much lower than expected.

When you sparge there will be some diffusion but their contribution to the overall efficiency is really small due to the small amount of wort that is actually held inside the grit particles. The majority of the wort is on the outside and lautering washes that into the BK. Technical brewing texts do mention that the actual diffusion takes some time and allowing it to happen is a reason for slow lautering. However, those books are targeted at (large) commercial brewers which do worry about efficiency changes as small as 0.5% and less. We home brewers can't even measure that accurate.

If you have low lauter efficiency due to sparging too fast (and that only applies to fly sparging) it is because of the formation of channels and not insufficient time for sugar diffusion out of the grain.

Kai

[nyakavt]

I know this is a bit late, but I thought about running sizes and batch sparging a bit and came up with an analogy that makes sense to me.  Imagine that you have a kettle that always leaves 1 gallon behind when drained.  So if you have 200 'points' of sugar and dilute it to make 5 gallons of wort, that's a 1.040 wort.  If the kettle is drained as much as possible, 1 gallon of 1.040 wort will be left behind, or 40 points out of a possible 200 (20%).  This is analagous to a no-sparge. 

Next collect the same amount of wort in two steps, first by collecting 3 gallons then collecting 1.  For the first runnings the wort will be 1.050 gravity, leaving 1 gallon behind.  Adding 1 more gallon of water will dilute the wort to 1.025, again leaving 1 gallon behind when drained.  So here you leave behind 25 points out of a possible 200, or 12.5%.  This is a single sparge with unequal runnings.

Finally, collect the same amount of wort in two equal steps.  This is done by a 3 gallon wort which is drained, followed by adding 2 gallons and again drained.  The first draining leaves 67 points behind, which is diluted to 1.022 by the second addition, and again leaving 1 gallon behind.  Here you leave behind 22 points, or 11%.  This is a single sparge with equal runnings.   

You can see the difference between equal and unequal runnings (1.5%) is relatively small even for a large difference in runoff sizes.  The size of the 'dead space' at the bottom of the kettle can be represented in your MT by the amount of wort absorbed by the grain and any dead space, easily measured on your next batch.

[Kaiser]

I know this is a bit late, but I thought about running sizes and batch sparging a bit and came up with an analogy that makes sense to me.  Imagine that you have a kettle that always leaves 1 gallon behind when drained. 

That's exactly how I have modeled batch sparging on various occasions.

Kai

[nyakavt]

I know this is a bit late, but I thought about running sizes and batch sparging a bit and came up with an analogy that makes sense to me.  Imagine that you have a kettle that always leaves 1 gallon behind when drained.  

That's exactly how I have modeled batch sparging on various occasions.

Kai

Yep, I've found your model to very accurately predict the into-kettle efficiency when all the starch is converted prior to the first runoff.  Since I got my refractometer inconsistencies sorted, my 3 most recent calculated efficiencies were within 1% of observed efficiency.  It's a very useful tool for recipe formulation and for seeing how much efficiency decline to expect when brewing bigger batches but collecting the same amount of wort.

[wilypig]

I think the reason to wait is not for added conversion but to ensure the proper contact time with the mash to ensure full solubility of the remaining sugars. This will also aid in efficiency

[denny]

I think the reason to wait is not for added conversion but to ensure the proper contact time with the mash to ensure full solubility of the remaining sugars. This will also aid in efficiency

Again, I've tried a lot of different methods and I've seen no difference.

[Kaiser]

Yep, I've found your model to very accurately predict the into-kettle efficiency when all the starch is converted prior to the first runoff.  Since I got my refractometer inconsistencies sorted, my 3 most recent calculated efficiencies were within 1% of observed efficiency.  It's a very useful tool for recipe formulation and for seeing how much efficiency decline to expect when brewing bigger batches but collecting the same amount of wort.

Thanks. It's always good to have some back-up from the observations that other brewers make.

Kai