Recirc/Batch/2-vessel sparge question...

[bwarbiany]

As I've pointed out, Dustin and I will soon be buying pumps and plan to do our first batch on the 2-vessel system this weekend. Basically it should combine some of the benefits of batch sparging with those of fly sparging, as well as ease simplicity and ensure full conversion of starches due to the recirculation.

But there's one issue that I"m not sure about. I've never batch sparged, always fly. So I've never had a situation where I needed to measure water for a batch. I measure for dough-in, but then sparge until I reach my intended volume. This time, though, I'll need to have a clear measurement of both mash and sparge water before beginning to be sure I end with the right volume (while not compromising efficiency or missing target volume).

I'll need to collect about 17 gallons of water.

I'll mash with 9 gallons of water (28 lbs of grain). Thus, I need to keep at least 8 more gallons on hand in the sparge tank. Then, I need to account for grain soaking up liquid. I've heard a number of 0.1qt/lb of capacity in the grain, so that leaves me with an additional 2.8 gallons of water lost to the grain. Last I need to consider dead space in the tun. Maybe 1.5 gallons for a keggle wth a false bottom?

Is this correct? If I start with a total volume of roughly 21-22 gallons, will I lose about 4.5 total to grain and dead space, and assume I'll end up with about 17 pre-boil?

edited to fix link: BB

[spkrtoy]

I think most brewing software has something in it to take out all the guesswork on volume of water. I don't know anything about batch sparging, so I'll leave that to the expert's.

[kevinham]

I am by no means an expert, but you are on the right track. Except grain absorption is .1gal/lb not qt, looks like you did the math right but typed the equation wrong. You will have to test out the mash tun to see what your loss is there. And like you said, subtract that from what you added initially to get your first runnings.

So for 28 lbs of grain, it should absorb 2.8 gal. Assuming 1.5 gal loss to dead space (I don't really lose anything in my cooler, so I don't know about your keg). If you added 9 gallons for the mash you will end up with 4.7 gal (9 - 2.8 - 1.5) for your first runnings. If you need 17 gallons pre-boil, you will need an extra 12.3 gal. For a total of 21.3 gal of water.

I don't know how your system will work, that link is still dead. But I like to split the sparge in two even batches (in this case two sparges of 6.15 gal). Some people like to mash out up to half of the pre-boil volume. So you would take an extra 3.8 gallons to mash out, to bring you up to 8.5. Then split the remaining 8.5 gallons into two sparges of 4.25 gal.

Make sense? Mike did I screw anything up?

[brahn]

Brad, your math looks good to me, like Kevin said. As far as dead space, it's pretty tough to figure that out without brewing a few batches. I think your initial guess is a good starting point, but you'll probably have to tweak it as you go.

As far as the batch sparging, it sounds like Kevin is saying that he drains his tun 3 times. I only drain my tun twice, once for the "mash" and once for the "sparge". I don't see any advantage to splitting it into more batches, it just takes more time. Like Kevin I do try to keep the runoff fairly even. In your case, I would mash in with 12.8G or more likely 13. That's 1.86qt/# which is perfectly acceptable. That should runoff around 8.7 G. Then I'd add 8.5G, stir, and runoff again. That should give you around 17G in the kettle. I also start heating the kettle after the first runoff.

[bwarbiany]

I fixed the link...

Basically the system recirculates the mash, then circulates the mash and sparge water together through the grain until the gravity of all liquid in the system equal. At that point, you can stop circulating from the boil kettle into the mash tun and simply drain the mash tun.

I think I may drop a few points efficiency compared to fly sparging, but at the benefit of completely removing the chance to oversparge and keeping the system compact and simple.

Based on my mash tun design, I might change my wort pick-up tube so it reaches nearer to the bottom of the tun... That should remove dead space, which in this system is more of a problem than a traditional system since the wort left in the dead space will be full of sugars.

[kevinham]

Brad, your math looks good to me, like Kevin said. As far as dead space, it's pretty tough to figure that out without brewing a few batches. I think your initial guess is a good starting point, but you'll probably have to tweak it as you go.

As far as the batch sparging, it sounds like Kevin is saying that he drains his tun 3 times. I only drain my tun twice, once for the "mash" and once for the "sparge". I don't see any advantage to splitting it into more batches, it just takes more time. Like Kevin I do try to keep the runoff fairly even. In your case, I would mash in with 12.8G or more likely 13. That's 1.86qt/# which is perfectly acceptable. That should runoff around 8.7 G. Then I'd add 8.5G, stir, and runoff again. That should give you around 17G in the kettle. I also start heating the kettle after the first runoff.

I like to do a double batch sparge without a mash out. I feel like it gives higher efficiency to sparge twice. I tried it based on a couple experiments that this guy Bobby did (http://www.suebob.com/brew/allgrain.htm). At the bottom of the page on that link he talks about it. I can't seem to find a link to his experiment, but I'll keep looking. Basically he tried it with a single sparge, a double sparge, and a mash out double sparge. He found for his equipment the double sparge with no mash out gave the highest efficiency.

It makes sense to me too. This is his analogy "Think of washing a glass in the sink. Which gets more soap off; filling it all the way, swishing it then dumping or filling it half way, swishing, dumping and repeating?"

Also I don't see why doing that would take more than a couple minutes longer.

I know a lot of people do it lots of different ways, so to each his own.

[kevinham]

I fixed the link...

Basically the system recirculates the mash, then circulates the mash and sparge water together through the grain until the gravity of all liquid in the system equal. At that point, you can stop circulating from the boil kettle into the mash tun and simply drain the mash tun.

I think I may drop a few points efficiency compared to fly sparging, but at the benefit of completely removing the chance to oversparge and keeping the system compact and simple.

Based on my mash tun design, I might change my wort pick-up tube so it reaches nearer to the bottom of the tun... That should remove dead space, which in this system is more of a problem than a traditional system since the wort left in the dead space will be full of sugars.

Yeah I remember seeing that thing before. Pretty good idea. I'm interested in knowing how it works for you.

Edit: So I guess the whole double sparge vs. single sparge doesn't matter in this case. Good luck with the build.

[backyard brewer]

I'm very curious to see how this works as well. I understand the concept, but it still seems like efficiency would be lower since you're not rinsing the grains. If it's a few points and can be made up for in just a couple pounds of grain then I'd be good with that though.

The cost of only 2 kettles versus 3 would make it worthwhile, not to mention the tighter footprint.

[bwarbiany]

I'm very curious to see how this works as well. I understand the concept, but it still seems like efficiency would be lower since you're not rinsing the grains. If it's a few points and can be made up for in just a couple pounds of grain then I'd be good with that though.

The cost of only 2 kettles versus 3 would make it worthwhile, not to mention the tighter footprint.

Well, if it works out, we might be selling some kegs, because we already have the extra kettles

As for the efficiency, I've heard that the wort's ability to dissolve the sugar means that you still won't be leaving much sugar in the grain. According to the Brutus link, it seems that he's dropped from 78% to 74% efficiency due to the change in method, but in the grand scheme that's not much of a difference.

I just like the idea (after dropping a full mash tun) of setting two kettles in place on burners, and not having to move them until it's time to clean them. If I don't like the way it works, I'll just switch over to a three-vessel system, because I've got enough burners and kettles to do it.

[Rezzin]

FYI, your 'absorption rate' might be slightly higher with more grains. If you give the tun plenty of time for that wort to make it's way through the grains and into your kettle, you'll be closer to the .1g/# rate. To clarify, the .1g/# is fairly accurate but you need to a little extra time for the extra wort at the top of the grain bed to trickle it's way down. Figuring out your loss from the false bottem and kettle loss should be easy.

Let us know how it goes!

I typically get 72-75% eff on my system with a batch sparge. It's pretty consistent so I've never bothered to change my mill gap settings or method at all. As long as I'm close, that's all that matters to me

[brahn]

FYI, your 'absorption rate' might be slightly higher with more grains.

I agree with Rezzin on this one, I doubled my batch size and I seem to be getting a higher absorption rate with the larger amount of grain. That or my math is all screwed up, which is certainly possible. My next batch will be my third at the larger size and I think I'll finally have it dialed in pretty well.

[Rezzin]

Brad, your math looks good to me, like Kevin said. As far as dead space, it's pretty tough to figure that out without brewing a few batches. I think your initial guess is a good starting point, but you'll probably have to tweak it as you go.

As far as the batch sparging, it sounds like Kevin is saying that he drains his tun 3 times. I only drain my tun twice, once for the "mash" and once for the "sparge". I don't see any advantage to splitting it into more batches, it just takes more time. Like Kevin I do try to keep the runoff fairly even. In your case, I would mash in with 12.8G or more likely 13. That's 1.86qt/# which is perfectly acceptable. That should runoff around 8.7 G. Then I'd add 8.5G, stir, and runoff again. That should give you around 17G in the kettle. I also start heating the kettle after the first runoff.

I like to do a double batch sparge without a mash out. I feel like it gives higher efficiency to sparge twice. I tried it based on a couple experiments that this guy Bobby did (http://www.suebob.com/brew/allgrain.htm). At the bottom of the page on that link he talks about it. I can't seem to find a link to his experiment, but I'll keep looking. Basically he tried it with a single sparge, a double sparge, and a mash out double sparge. He found for his equipment the double sparge with no mash out gave the highest efficiency.

It makes sense to me too. This is his analogy "Think of washing a glass in the sink. Which gets more soap off; filling it all the way, swishing it then dumping or filling it half way, swishing, dumping and repeating?"

Also I don't see why doing that would take more than a couple minutes longer.

I know a lot of people do it lots of different ways, so to each his own.

It's probably not but it has me wondering, would there possibly a pH issue with that last sparge? If you have a refractometer, can you check the brix of your final runnings the next time you brew?

[backyard brewer]

As for the efficiency, I've heard that the wort's ability to dissolve the sugar means that you still won't be leaving much sugar in the grain. According to the Brutus link, it seems that he's dropped from 78% to 74% efficiency due to the change in method, but in the grand scheme that's not much of a difference.

So the theory here is that the wort is no where near super-saturated and therefore dissolves all the sugar it's going to within a few points? I don't hit 78% now but a couple points is just not a big deal.

I like this more and more.

[bwarbiany]

It's probably not but it has me wondering, would there possibly a pH issue with that last sparge? If you have a refractometer, can you check the brix of your final runnings the next time you brew?

I think it's unlikely. One of the advantages to batch sparging is that it is difficult to oversparge, because there is almost always enough sugar left in the mash/wort to keep the pH low enough. I'm sure on very low-gravity beers, your third sparge might drop too low, but I doubt it would be likely to be low enough unless you tried to take this method to the extreme and did 4-5 or more steps of sparge.

But either way, for any beer, batch sparging is less likely to oversparge because the final sparge is uniform in gravity instead of high gravity at the beginning and low gravity at the end.

[Oskaar]

Remember that sugar and pH are not always limiting factors to one another. It is common to have a honey or grape must that is over 26 brix with a pH of 3.2 or lower, and I've also seen this in braggots and high gravity all grains. Just be aware.

Cheers,

Oskaar