Batch v Fly. Pro's and Con's?

[Martin the fish]

Currently i fly sparge. Don't think i could batch sparge with a 8-9kg grain bill in my mash tun anyway? I could with a 4-5kg grain bill though

Which made me think. What are the pro's and con's of both methods?
I find that fly sparging suits me at the moment-especially now i've got my new taps fitted.
When would you batch sparge as opposed to fly sparge and vice versa? Should i try a batch sparge myself? Or should i stick with fly sparging if i'm happy?

[delboy]

This is one of those issues that seems to split people down the middle and results in heated debates (on other HB forums anyway).
To be honest i think its much of a muchness and if you have a system that works for you stick with it.

At the moment im batch sparging but thats just because its easier than fly (for me) but im sure that if i managed to get the fly sparging semi way automated i'd be happy doing that too.

[mysterio]

I fly sparge because it's what i've always done and I'm comfortable with it. I've got it tuned so that I can just leave it for 45 mins and do something else. That is the big advantage to me, that if you know how to control the flow you can just let it be. Plus i've got one of those Phil's sparge arms and it would be rude not to use it.

I've never tried batch sparging but I undoubtedly will at some point. A big advantage seems to me to be that it doesn't matter how your lauter tun is designed. With batch sparging, you are putting all of the sugars into solution and then draining them out so it doesn't matter if there is only one collection point in your lauter tun. With fly, if you only had one collection point you would almost certainly take a hit in your efficiency. I'm currently building a new mash tun from a stainless stock pot and will probably use my old copper manifold until I get a false bottom, so i'll probably batch sparge in the intirim.

[BlightyBrewer]

There's an article about the pro's and cons of batch and fly sparging in BYO this month.

[Martin the fish]

I know the difference in the basic terms-i just wondered who prefered one to the other and for what reason.
There doesn't seem to me, that there should be much difference in the outcome. I'm guessing it boils down to who has an automated fly sparge set-up and who doesn't.

[mysterio]

Like you said, each has their pros and cons. Fly-spargers will usually claim that you can get a better efficiency with their method (depends), Batch spargers will sometimes claim that they don't have to worry about Ph during the sparge (again, depends).

[Martin the fish]

Very interesting points DaaB.

[subsub]

Big grain bill - Fly, small grain bill - Batch

[des]

If you have a big grain bill then, what would be the effect of batch sparging in more than 2 batches?

[nobby]

I batch sparge, when I had a square cool box I got about 70% efficency. now I have changed to a shiney Thermobox I am getting 80%

[prolix]

I fly sparge mainly, have batched a few times for speed brewevenings but the calculations for some reason unbeknownst to me ( maybe the TC I drink during the mash ) always come up short, I know add more water then, but it could be that I never accurately measure the mash liquor I have a stick with a notch on it

[Whorst]

I batch sparge. My efficiency is only 60%. Not a problem. I just usually add 2 extra pounds(non-sterling) of malt to make up for the lack.

[mitch]

If you have a big grain bill then, what would be the effect of batch sparging in more than 2 batches?

Lower efficiency.

DaaB, do you say this based upon personal experience or received wisdom?

I ask because, for a fixed total volume of wort collected, the theory says that increasing the number of sparges will almost always increase your efficiency. The intuative explanation is that your efficiency is a measure of the proportion of sugars that you fail to extract from the grain, which is directly proportional to the gravity of your last sparge. It is almost always true that the more sparges you do, the lower the gravity of the final sparge , and so the less sugars you leave behind and the higher your efficiency.

Anything that decreases the gravity of your final sparge will increase your efficiency. An obvious way of decreasing the gravity of the last sparge is to collect more wort. A less obvious way is to collect equal volumes of wort at each sparge. Although this last point is the one usually obsessed about, the theory says that it actually has a very small effect compared with the other two. For example, collecting 30l of wort as 10l + 4l + 16l will (acording to the theory) be more efficient than two sparges of 15l each.

[eddetchon]

Mitch
Which theory are you referring to? The mathematically minded may wish to work through the formulae outlined in this page:
http://www.franklinbrew.org/brewinfo/nbsparge.html
and in particular, the discussion that begins under the heading "Batch Sparge recipe analysis" and even more so that which begins from the words "Let's digress for a moment and see if we can optimize the extraction of sugar into the boiler for [batch sparging]".

This demonstrates that the most efficient way of batch sparging is for there to be two runoffs of equal volume. ie. that the volume of liquor in the mash prior to first runoff must equal the volume of water to be infused in the second "batch sparge". My understanding is that this depends on you working with a fixed volume to collect. With bigger mashes I have often considered whether it would be worth doing a third, much smaller, sparge, to collect whatever is left (probably quite a bit), and then boiling for longer - but that's a slightly different issue, and you get to the point where you might as well fly sparge.

[Gurgeh]

i batch sparge, but last brew i managed to up my efficiency from a tasty 65% to a more frugal 70%

I suspect because i drained off the mash first instead of topping it up straight away.

I wanted to collect 28L and so i subtracted the amount run off from this, divided by 2 and used that figure for my 2 equal batches.

Nice and easy!

i don't fly-sparge because it takes too long!