# Equal Mash and Sparge Runoff Volumes

I’ve read several posts stating that for optimum efficiency when batch sparging, you should ensure your mash and sparge runoff volumes are equal. Why?

If you want to wade through the math, the answer is here

The reality is that as long as the 2 volumes are within a gal. or so of each other, that’s plenty close enough.

Are there any published experiments proving this model, or has anyone around here conducted experiments that prove it?

I’m a bit puzzled because I got excellent results over the weekend using a 1:2 ratio. According to Beersmith I got 80% brewhouse and 90% mash efficiency.

[quote=“kcbeersnob”]Are there any published experiments proving this model, or has anyone around here conducted experiments that prove it?

I’m a bit puzzled because I got excellent results over the weekend using a 1:2 ratio. According to Beersmith I got 80% brewhouse and 90% mash efficiency.[/quote]

Ken’s work in that link is as close as I know of. It was first presented at the NHC in 96 or 98 in PDX. As you proved, there’s theory and then there’s reality. For example, Ken talks about a grain scale up factor for batch sparging. When he was developing his spreadsheet, I’d send him my numbers and I was always way over the predicted OG. Turns out that by using the scale up factor I was using too much grain. So, what works for is the right way to do it. Have you done this more than once to verify it?

My most recent batch was only my 4th all grain batch, so am still fine tuning my procedures and have not had a chance to try repeating my most recent results. I can only brew every 3-4 weeks usually. I will continue using this technique to see if I can get consistent results for…um…science.

I overshot OG on this batch, so I guess you could say I used too much grain. I was budgeting conservatively for 76% efficiency. I’ll definitely bump that up now that I feel confident in my procedure. We’ll see what happens to my efficiency if I use less grain.

How big was the beer? According to Kai’s work
http://braukaiser.com/wiki/index.php?title=Batch_Sparging_Analysis
, which has always been predictive for me, to get 90% lauter efficiency with a single batch sparge you have to use, at most, 8-9 lb of grain. And that assumes equal runnings. How confident are you in your measurements?

Kai’s work shows that anything between 30% to 70% will be within 1% of 50:50.

http://braukaiser.com/wiki/index.php?ti ... _ratio.gif

RDWHAHB

How big was the beer? According to Kai’s work
http://braukaiser.com/wiki/index.php?title=Batch_Sparging_Analysis
, which has always been predictive for me, to get 90% lauter efficiency with a single batch sparge you have to use, at most, 8-9 lb of grain. And that assumes equal runnings. How confident are you in your measurements?[/quote]

The grain bill was 9.5 pounds. 100% confident in the measurements.