Designing a batch sparge experiment

Beertoven and I just had a little sidebar in an unsuspecting recipe thread about batch sparge methodology. If you've seen my all grain page (www.suebob.com/brew/allgrain.htm) you know that I like to use a hot double sparge in lieu of doing a pre-runnings mash out infusion. The reason I do this, and recommend it, is that I've tried a few methods and have had best results. However, I've never tested it with more controls and data points. It's been generally empirical, but variables can get the best of you. I don't want to keep advocating something that may be errent.

I'm constructing an experiment using 3 samples. All will be mashed at the same time for the same duration/temp (sitting in a common water bath to prevent drift). The sparge will use exactly the same volume so all three preboil volumes will be identical. The variables:

1. Pre-running mash out infusion at enough volume to raise mash to 168F, drain, infuse remaining sparge volume @ 168F and drain. (MOSS)

2. Full drain, full volume sparge infusion at 180F, drain. (NMOSS)

3. Full drain, half volume sparge infusion at 180F, drain, second half volume, drain. (NMODS)

Compare OG. Highest wins. Debate solved... heh, yeah right.

What I expect is that #3 will be the highest efficiency, somewhere around 94% followed closely by #1 at about 91%, then #2 at about 85%.

No, it's not touching on fly sparging, wort quality, hot side aeration or tannin extraction. It's just about maximizing batch sparge efficiency. Waste of time or interesting? Thoughts?

That's a great experimental design, Bobby. I'm a double batch fan as well and have been wondering(I was in on that thread w/ Beertoven as well) if I'm REALLY doing the best I can from an efficiency perspective.

Thanks, as usual, for doing the legwork!

This looks neat, Bobby. How are you actually going to carry it out? I'd like to replicate this at my house if I can. Ideally, the experiment would be carried out several times and then average OG's compared.

Dr. Bobby with another mad scientist experiment.


I like it!

cool idea -- it would be interesting to know if you could taste any differences in the batches in double blind taste test too.

Thats a great idea. Please post your results

Yeah! I'm VERY interested in the results, due to having limited mashing capabilities (5gal). I've always been told a mashout is unnecessary when using batch sparging, so i'm curious as to which turns out "optimal".

I would suspect that you would need the same result a number of times before you can come to a conclusion. There are variables which can't easily be controlled like the thoroughness of stirring and the efficiency of the grain bed.

Great experiment. I was wondering what volume of grain you are using and the thickness of your mash? I am curious what would happen if you repeated this triple experiment three times at three different grain bills, say a 5 gallon batch with 6 gallons of wort collected for 8 pounds, 12 pounds, and 16 pounds of grain. That way you could plot efficiency curves for different size grain bills.

I would be willing to help foot the bill for some of the grain as well as assist in "disposing" of some of the resulting output of the process.

Hey, I'm a fan of your page and your process so I'm always interested in your proofs! Thanks for sharing!

I'm focusing on an OG that I use most often because those results are going to be most meaningful to me; probably 1.060 as it's about the upper range for 90% of my beers. I'm not sure that grain bill is going to affect the overall relationship between the methods. I mean, if there are 2% efficiency variences between each sample at 1.050 OG, it would probably be a similar varience at 1.090, though all the numbers would drop.

I plan to scale down to really small samples so I can conduct the 3 mashes in my 48qt cooler in their own isolation containers. To make the numbers easy, I think each batch will be .5 gallons so I'll go with 14.5 oz and get a preboil of volume of 1 gallon.

Chris_Dog said:

I would suspect that you would need the same result a number of times before you can come to a conclusion. There are variables which can't easily be controlled like the thoroughness of stirring and the efficiency of the grain bed.

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I'm all for thorough repeated tests but it's hard enough pulling it off one time. Are you telling me that if I find 3% efficiency difference between all three samples that it's a meaningless result? I think it's better data than "I tried a few different methods over the course of a few batches and found x to be better".

I do like this idea and look forward to hearing how it turns out.
But truthfully, I feel that repeatability is more important the efficiency.

It's kind of like my car. Sure if I hookup I can pull high 11 sec 1/4 mile runs but I can't get it every time. But I can hit mid 12's every time.

Bobby_M said:

I'm all for thorough repeated tests but it's hard enough pulling it off one time. Are you telling me that if I find 3% efficiency difference between all three samples that it's a meaningless result? I think it's better data than "I tried a few different methods over the course of a few batches and found x to be better".

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I don't think your results will be meaningless. They would, in fact, be very helpful. They represent a good-faith attempt to isolate the effect of batch sparge methodology on extract efficiency, controlling as many variables as reasonable in a single application. Of course, if you did do it multiple times then that would strengthen the results.

Hopefully your method will be easy enough that other brewers can carry it out on their own setups. If no-mashout-double-sparge really is the better method (conjecture!), then other brewers should be able to replicate that result within reasonable tolerances. If everyone who does this reports their results, then eventually the weight of evidence will become hard to ignore.

Personally, I like the "I tried a few different methods over the course of a few batches and found x to be better" approach as well. As long as good records are kept and the results are interpreted appropriately those types of reports are useful too.

Wow, this post has raised all kinds of issues for me (in a good way). In my work I use non-experimental quantitative data all the time to draw conclusions and make recommendations. Occasionally I have to defend my work to someone who thinks that randomized controlled designs are the only way to do "real" science. They are not.

Bobby_M said:

I'm all for thorough repeated tests but it's hard enough pulling it off one time. Are you telling me that if I find 3% efficiency difference between all three samples that it's a meaningless result? I think it's better data than "I tried a few different methods over the course of a few batches and found x to be better".

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I agree whole hearthedly, I was just playing the devils advocate. I do think you findings need to be validated is all.

Maybe I can help out after your test.

FSR, yeah, consistency is very important too but I'd rather use a consistent high efficiency method than a low one ya know. I'm not saying I'd ever choose a certain method every once in a while. I've been sticking with what appears to be the highest efficiency producer for me but I want to verify that it's not a fluke.

Bobby_M said:

FSR, yeah, consistency is very important too but I'd rather use a consistent high efficiency method than a low one ya know. I'm not saying I'd ever choose a certain method every once in a while. I've been sticking with what appears to be the highest efficiency producer for me but I want to verify that it's not a fluke.

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Yes so I think that repeating this on different days (in a little different conditions) may show that one is better then the other.

Funny....when I moved to 10 gal batches I ran into a problem with my cooler only have enough room for grain and mash water. Then when it came time for sparging(not fly) I had to split it into two. I have hit mid 90%'s since! It works for me.

Hope to hear how your experiment turns out!

Brewnurse said:

Funny....when I moved to 10 gal batches I ran into a problem with my cooler only have enough room for grain and mash water. Then when it came time for sparging(not fly) I had to split it into two. I have hit mid 90%'s since! It works for me.

Hope to hear how your experiment turns out!

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I do two sparges and a mashout. Get low 80's every time.