Does Sparge Water Volume Affect Efficiency?

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ultravista

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Does the volume of sparge water effect efficiency? In other words, I have read (posts here) that the volume of sparge water impacts efficiency. Too little water results in poor efficiency ... to much water can do the same.

Is it simply a matter of pulling the sugars off the grain? Is there a benefit of recirculating the "sparged" water to maximize the sugar pull while maintaining volume?

I presume too much sparge water "waters down" the wort, correct?
 
The science/research shows that your maximum efficiency typically comes when you yield half your boil volume from your mash and half from your sparge. You won't lose much efficiency if you're fairly close to half with each (60/40 for example), but the further away you get the more efficiency you'll typically lose.

I recommend going to www.braukaiser.com to read his research. Great site with great information.

Keep in mind, there is much more to efficiency than just this of course. I typically tell people to two items that I feel are very important are getting a fine crush on your grains and draining that tun dry (relatively speaking).

Good luck.

cp
 
... but can you explain why sparging with less water decreases efficiency? In other words, less sugars washed off the grains? I am confused as to the volume of water used, whether it be 2, 3, or 4 gallons, unless it's about pulling the sugars out.
 
It depends somewhat on your sparge method, but basically too little sparge water and you won't adequately wash the sugars from the grain bed. Too much and your boil volume will be too large and you won't hit your target gravity.

Also, over-sparging can lead to tanin extraction and give you some astringent off flavors.

Efficiency is about two things - conversion and extraction. conversion is effected by the amount of water in the mash, too thick and you won't get very effective conversion, to thin and you won't have the boil volume left for a complete sparge (thus lowering extraction).

Batch sparging seems to be less sensitive to the sparge/mash volume ratio, but I don't have hard data to back that up, only my annecdotal experience. But the total efficiency also appears to be less than with a properly run fly sparge.
 
Well, besides not getting enough sugar out of the grain, too little sparge water means that you'll end up topping off with water because you'll boil down past your batch size.

If you want 5 gallons in the fermenter, you start with about 6.5 gallons preboil. This is a combination of unabsorbed mash liquor/wort and whatever you sparge with. It gets a little more complicated when you differentiate between batch and fly sparging.
 
Interesting question, one I have considered myself.

I brewed a doppelbock a while back with what should have been a high OG. It was only a 5 gal batch. When i had about 6 gallons in I took an OG reading and found it too low. I took a refractometer reading on the current outflow from the sparge and found it still fairly high, meaning sugars were still coming out of the grain. I sparged another 3 gallons or so and boiled a few extra hours. In the end I came out with the right gallons and OG. I asked here why I had to do the extra sparging and boiling but did not get a good reason.

I would just aim for 50/50 mash/sparge. You can also buy a refractometer and take small samples at any temperature of the outflow and boil pot to help you decide when to stop sparging.
 
Brewhouse efficiency is a complicated beast in general... if you actually start accounting for all of the factors it can be overwhelming. I threw in the batch v. fly because I think it's important to recognize the difference. Other than that, use the 50/50 rule to hit your pre-boil volume, relax and have a beer ;-) cheers!
 
The 50/50 is optimal because you're allowing two even amounts of water/liquid to bring those sugars into the boil kettle. If you have 60/40 I don't think you'd notice much difference.

I'm certainly no expert. I'd recommend reading Kai's research/experiment and you'll see the results for yourself.

Also, when you say too much sparge water would water down the wort that isn't necessarily correct. If you are hitting your target boil volume with that sparge then it's not so much about watering down the wort as it is about leaving sugars behind in the kettle if aren't hitting your expected efficiency. Watering down the wort would be using too much water overall and hitting a much higher pre-boil volume than you should.

My words of wisdom:

1. Use the 50/50 rule.
2. Get a fine crush on your grain.
3. Drain your tun dry (relatively). If you don't, you're leaving efficiency behind in the tun that should be in your boil kettle.

If you want a spreadsheet that is set up for batch sparging utilizing the 50/50 rule just pm me your email address. It will take care of all the math (and much more) for you so all you'll need to do is brew.

Good luck.

cp
 
I started hitting my efficiency when I started using a 50/50(25/25) ratio. Mash net total volume being 3.5 gallons. First batch sparge will be 1.5 gallons second is usually 1.5 gallons. The first sparge should last at least 30-40 min the second one is much faster, around 5-10 minutes. It works for me most times
 
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