Batch sparging the dead zone

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Judochop

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I’m considering switching to a batch sparging method for my small to medium sized beers, but as I was thinking through the process, I came upon a concern.

The set-up: I’ve got a 10 gallon stainless steel MLT with a dead space that may be 2 gallons. (I haven’t measured it yet, but I’m pretty sure it’s well beyond 1 gallon.)

I want to collect 7 gallons pre-boil, thus I plan to collect 3.5 gallons in my first run-off. But even at a humble 9 lbs of grist, I’ve got 3 gallons of mash water mixed in there plus another 2 gallons below in the dead space. Minus roughly a gallon of absorption, I’m still looking at 4 gallons in my first run-off.

Now, if I simply add another 3 gallons to the MLT, I see 2 gallons of that water going straight to the dead space, leaving me with only 1 gallon to stir into the grains and rinse the sugars. Is that enough water? Am I going to have a hell of a time stirring a ‘mash’ this thick? I feel like most people doing batch sparge are using igloo coolers with dead spaces much smaller. I don’t know why I feel that way… it’s just an instinct.

Any batch spargers out there with words of comfort, or better yet, a MLT like mine?
 
2 gallons of deadspace is unacceptable should be corrected. How about a picture of the setup? What kind of separation medium do you have in there? False bottom?
Why is your deadspace so large? Just to make sure we're talking about the same thing, if you fill your MLT with 4 gallons of plain water and open the valve, are you saying only 2 gallons will drain out? You need a siphon tube to the bottom of the tun.
 
By dead space, I assume you mean space below the false bottom and not the volume left after draining. What I would do is drain the first 2 gallons into a separate pot and drain the rest of the first runnings into the kettle. Then pour the first two gallons back into the mash tun and add the sparge water.
 
By dead space, I assume you mean space below the false bottom and not the volume left after draining. What I would do is drain the first 2 gallons into a separate pot and drain the rest of the first runnings into the kettle. Then pour the first two gallons back into the mash tun and add the sparge water.
D'OH!

<sheepish>

(Yes... that is what I meant by dead space; the space under the false bottom.)

Thanks for the idea! I may have been as premature with my estimate as I was wrong about my use of the term 'dead space'. I will do an exact measurement tonight! (But for the record, I do think it's more than a gallon. It's an older-model MLT from Morebeer.com with the stainless false bottom.)
 
By dead space, I assume you mean space below the false bottom and not the volume left after draining. What I would do is drain the first 2 gallons into a separate pot and drain the rest of the first runnings into the kettle. Then pour the first two gallons back into the mash tun and add the sparge water.

I'm confused... what exactly would this accomplish?
 
If you're batch sparging, you could tilt the MLT in the direction of the outlet. Dead space will drop to an insignificant amount.

-a.
 
I'm confused... what exactly would this accomplish?

I'm not quite following either. You'll definitely have to run a slightly thinner mash, but you certainly want to drain off all the wort in first runnings if batch sparging is desired. Tuns with false bottoms like this are better for fly sparging.
 
Pictures would be fantastic. Depending on your setup it may be just a matter of altering your diptube/false bottom.
 
Thanks fellas. Tonight I'm going to get some real numbers (like the actual volume under the false bottom) and some pictures for the gang, and will have them back up here in the morning.

I&#8217;m starting to get the feeling that my system just ain&#8217;t cut out for batch-sparging. I may be a fly-guy by necessity. Presuming my estimate of a 2-gallon space below the false bottom is correct, if I ever wanted to do a double batch-sparge, I&#8217;d be having to split a piddly 2-3 gallons of water between the two sparges, and losing almost all of that sparge water to the space below the FB. That doesn't seem practical at all.

A question to those who do batch sparge&#8230; how much initial run-off do you typically get in your systems, and how much sparge water are you subsequently using? And what are those systems? I&#8217;d like to know just how different my set-up is from others&#8217;.
 
Here's my thinking:

The volume under the false-bottom hasn't been in contact with the grain and is basically just water. Therefor, by recycling it, he can use it to rinse some of the sugars from the grains and then the additional sparge water will be concentrated in the grain bed.

This, of course, is invalid if he has a recirculation system.

OP - I have a bazooka tube in my tun and essentially no dead-zone. my runnings go: 25%, 37.5%, 37.5%.
 
Here's my thinking:

The volume under the false-bottom hasn't been in contact with the grain and is basically just water.

I dont understand that logic.
It hasnt been in contact with the grain but it is in contact with the water that is in contact with the grain. So it would be wort. Sugars dont get stopped by the false bottom.
 
Here's my thinking:

The volume under the false-bottom hasn't been in contact with the grain and is basically just water. Therefor, by recycling it, he can use it to rinse some of the sugars from the grains and then the additional sparge water will be concentrated in the grain bed.

This, of course, is invalid if he has a recirculation system.

OP - I have a bazooka tube in my tun and essentially no dead-zone. my runnings go: 25%, 37.5%, 37.5%.

Lost me on that one, how would the liquid under the false bottom be just water? The false bottom is just a giant braid. The grain sits on top and the hot water runs down through the grain, through the false bottom.


Unless I am not understading something.
 
Here's my thinking:

The volume under the false-bottom hasn't been in contact with the grain and is basically just water. Therefor, by recycling it, he can use it to rinse some of the sugars from the grains and then the additional sparge water will be concentrated in the grain bed.

This, of course, is invalid if he has a recirculation system.
I’m fairly certain that I’m getting plenty of sugars in the space under my bottom (so to speak) because I’ve tasted it when I vorlouf. It’s usually quite colorful and sweet. So I’m thinking, as others are, that pouring it back into the mash would be futile.
OP - I have a bazooka tube in my tun and essentially no dead-zone. my runnings go: 25%, 37.5%, 37.5%.
For 7-gallons pre-boil, 25% would be 1.75 gallons. (Amazing, aren’t I?) But how can you guarantee that number when the amount of mash water you use is going to vary depending on your grain bill? Or do you forget about trying to hit a target pre-boil volume, collect your first runnings, and force the subsequent sparge volumes to their respective proportions of 37.5%? I can’t imagine that. If you’re working with a 15lb grist, you’ll be mashing with somewhere around 5 gallons of water, which means you’ll be collecting 3-4 gallons in the first run-off, which means that your total pre-boil volume would have to end up in the 12-16 gallon mark.

Can you illustrate (in terms of water and wort volumes) what a brewday looks like for you between an 8 lb grist and a 15 lb grist? Batch sparging looks like fun. I may consider scrapping my current set-up to get myself there, but I’m obviously very confused at this point.
 
Your situation requires a bit of reflection. First, why do you have a keg based mash tun? The typical reason for a metal tun is ability to direct fire it. If you're not doing that, then you might as well use a cooler. Another reason for metal might be durability but you also have a trade off in weight and lack of insulation. I went from 88-92% brewhouse efficiency using a cooler down to about 75% using a keg with false bottom just so I can direct fire for step mashes. Now that I don't really see the benefit of step mashing, I'm on the fence about my tun.

With 2 gallons under your FB, you're looking at running 1qt/lb + 2 gallons as a minimum thickness. Let's say a 10 gallon batch with 20lbs of grist: 5 gallons + 2 gallons. It will stir like a thick mash and you'd benefit from recirculating the liquid mash from below the FB at least a few times over the mash. After absorption, you'd run off about 4.5 gallons. Now you need to sparge with about 8 gallons which you COULD breaking into two 4 gallon infusions/drains. If not, you could have added 2 gallons prior to first runnings. In any case, a 6 gallon sparge in 20 lbs of wet grist is not unreasonable by any means, even if 2 of that is below the FB. You DO however want to recirculate at least two gallons back over the mash after stirring to make sure it's homogeneous before runoff.
 
Your situation requires a bit of reflection. First, why do you have a keg based mash tun? The typical reason for a metal tun is ability to direct fire it. If you're not doing that, then you might as well use a cooler. Another reason for metal might be durability but you also have a trade off in weight and lack of insulation.
It’s not a converted keg. It’s essentially a 10-gal brewpot w/thermometer and a solid, flat, removable false bottom. I did choose it for the ability to apply direct heat. Though I’ve come to realize that step mashing isn’t necessary, I still like being able to heat my mash water in my mash tun and dumping the grains in after. And in the summer/spring/fall, I don’t suffer any insulation issues at all. (I toss a wool blanket over it and it holds temp just fine.) But I’m not that attached to it, either.
With 2 gallons under your FB, you're looking at running 1qt/lb + 2 gallons as a minimum thickness. Let's say a 10 gallon batch with 20lbs of grist: 5 gallons + 2 gallons. It will stir like a thick mash and you'd benefit from recirculating the liquid mash from below the FB at least a few times over the mash. After absorption, you'd run off about 4.5 gallons. Now you need to sparge with about 8 gallons which you COULD breaking into two 4 gallon infusions/drains. If not, you could have added 2 gallons prior to first runnings. In any case, a 6 gallon sparge in 20 lbs of wet grist is not unreasonable by any means, even if 2 of that is below the FB. You DO however want to recirculate at least two gallons back over the mash after stirring to make sure it's homogeneous before runoff.
It’s only a 10-gallon pot, so I’m only doing 5-gallon batches.

So, modifying your example:

1qt/lb +2 gallons and 10 lbs grist = 2.5 gallons + 2 gallons
Lose about 1.25 gallons to absorption.
Run-off = 3.25 gallons.
Need to sparge with ~ 4 gallons.
Considering I’d do two batches, that’s 2 gallons each, and I’m suffering a 2-gallon space below the FB. That looks like trouble. If I ever wanted to do a thinner mash than 1qt/lb, I'd be in even more trouble.

It seems to me that I have two options:

a) fly-sparge as I’ve been doing
b) get new gear
 
Cool. Thanks Bobby_M.

If I can ask another pretty basic question... how do you get your sparge water from your HLT to the MLT? Gravity? Pumps? Manual scooping with a pitcher?

If I'm going to re-invent my system, I want to do it once and do it right.
 
Depends on what you want to spend. A three teir gravity fed system works fine and is probably the cheapest by a large margin. A 1-or 2 tier also works well, but requires at least one pump.
 
While I was racking my Saison to the secondary last night (tasting perfect, I&#8217;m pleased to say) I measured the volume under the false bottom in my mash tun: 1.5 gallons.

I really think this is a frustrating part of my system as it tends to throw off my numbers when I try to calculate the water I need to sparge, (assuming I&#8217;m headed for 7 gallons pre-boil).

It seems no matter how I figure it, I&#8217;m not going to be able to double batch-sparge. Thanks to a 1.5 gallon space under my FB, I&#8217;ll always obtain a fairly high amount of wort in my first runnings, which means I&#8217;ll be splitting very little sparge water between the two batch sparges, and that problem is made worse with the fact that what little sparge water I&#8217;m using is going to drop straight into that vortex under my FB.

Even fly-sparging is a bit weird; an average grain bill of 12 lbs @ 1.33q/lb is going to give me a 4-gallons to collect from the mash, and I only get 3 gallons to rinse with. It&#8217;s hard to make 3-gallons last 60 minutes.

I think for a 60-shilling or a mild I can get away with a single batch sparge pretty well. Since thick mashes are conducive to these styles, I could do a 1qt/lb mash ratio in 7-8 lbs of grist. This would leave me with about 2.5 gallons run-off, and 4.5 gallons to sparge with. My vortex would suck up 1.5 gallons, leaving me with 3 gallons for rinsing.

Does anybody else work with such a large volume of liquid under the false bottom?
 
Even fly-sparging is a bit weird; an average grain bill of 12 lbs @ 1.33q/lb is going to give me a 4-gallons to collect from the mash, and I only get 3 gallons to rinse with. It’s hard to make 3-gallons last 60 minutes.


Does anybody else work with such a large volume of liquid under the false bottom?

Well, technically you're taking 60 minutes (which is arguably a little lengthy for a 5 gallon batch) to runoff 7.5 gallons, not 3.

There are actually two trains of thought on fly sparging;

1. Add only enough sparge to reach your preboil volume so that the last of the runnings causes a dry grainbed.
2. Keep adding sparge until you reach your runoff volume. You'll leave a bunch in the tun at the end but it's super low gravity and helps keep the bed from compacting.
 
Well, technically you're taking 60 minutes (which is arguably a little lengthy for a 5 gallon batch) to runoff 7.5 gallons, not 3.

There are actually two trains of thought on fly sparging;

1. Add only enough sparge to reach your preboil volume so that the last of the runnings causes a dry grainbed.
2. Keep adding sparge until you reach your runoff volume. You'll leave a bunch in the tun at the end but it's super low gravity and helps keep the bed from compacting.
The downside of #1 is what? Risk of compacting the bed? If so, I don't see how doing this is any different than what I'd do during batch sparging. Both require a complete drain, albeit I'm doing it more slowly during fly-sparging. Is it the slowness that incresaes my risk of compacting? I'd think it'd be the opposite.
 
While I was racking my Saison to the secondary last night (tasting perfect, I’m pleased to say) I measured the volume under the false bottom in my mash tun: 1.5 gallons.

I'm shocked you have that much dead space. Do have a pickup tube installed off of the wort side of the spigot?
 
I'm shocked you have that much dead space. Do have a pickup tube installed off of the wort side of the spigot?
Just to be clear, it's not 1.5G 'dead' space. I misused the term in the OP. It's just the volume under the false bottom I'm talking about.

As far as actual 'dead' space I'm dealing with (the volume under the wort side opening of the spigot), it's pretty minimal. Probably not perfect, but nothing to freak out over.
 
Does anybody else work with such a large volume of liquid under the false bottom?
I do...I use a Zapap (bucket-in-a-bucket) lauter tun and there is quite a bit of space between the bottoms of the two buckets.

But it's totally not a problem...for fly-sparging. A system like this is set-up great for fly-sparging and imo batch-sparging with such a setup is a mistake. While there is a large amount of dead-space below the false-bottom...the valve is at the very bottom so only about 1.5 cups remains after I've fully drained it (and tilted it a little).

I do exactly what david mentioned earlier in the thread: I prefill the dead space with hot water, add the mash, start vorlauf. I save the first gallon or so of run-off (which is very low grav wort...mostly water) and pour it back on top of the grain bed...then I start adding the sparge water. My system seems to have a limit to how much sparge water I can use...most beers get 18 qt. sparge water (for a 5.5 gallon batch). No brew gets less than 16 qt. and no more than 20 qt. I have tweeked my efficiency up to 90% brewhouse (into-the-fermenter) but I have purposely scaled it back in an effort to ensure good wort quality...I'm @ about 85%.

Since thick mashes are conducive to these styles, I could do a 1qt/lb mash ratio in 7-8 lbs of grist. This would leave me with about 2.5 gallons run-off, and 4.5 gallons to sparge with. My vortex would suck up 1.5 gallons, leaving me with 3 gallons for rinsing.
1 qt/lb with 8 lb malt is only 2 gallons of water. How are you getting 2.5 gallons run-off...especially since the grain wil absorb some of that 2 gal. of water you added?

I have a spreadsheet I made that I use to calculate volumes. I'll try to remember to plug your numbers in and see what I get.

But imo, the bottom line is: your system is not conducive to batch-sparging and is perfectly set-up for fly-sparging. So I would def fly-sparge.
 
Just to be clear, it's not 1.5G 'dead' space. I misused the term in the OP. It's just the volume under the false bottom I'm talking about.

As far as actual 'dead' space I'm dealing with (the volume under the wort side opening of the spigot), it's pretty minimal. Probably not perfect, but nothing to freak out over.

Ah gotcha.
 
Draining too fast and (to a lesser degree) letting the wort level get below the top of the grain bed and then adding a bunch of sparge water can both compact the grain bed. Better to start draining too slow than too fast...you can always speed it up and imo the most important time to be draining slowly is at the very beginning. Towards the very end I often just open the valve full open...I definitely do that when I think the wort level is below the false-bottom.

FWIW, I do #1 in BobbyM's post but add just a little extra. I add about 2 quarts extra water and then save the last 2 quarts of runnings for yeast starters.
 
I do exactly what david mentioned earlier in the thread: I prefill the dead space with hot water, add the mash, start vorlauf. I save the first gallon or so of run-off (which is very low grav wort...mostly water) and pour it back on top of the grain bed...then I start adding the sparge water. My system seems to have a limit to how much sparge water I can use...most beers get 18 qt. sparge water (for a 5.5 gallon batch). No brew gets less than 16 qt. and no more than 20 qt. I have tweeked my efficiency up to 90% brewhouse (into-the-fermenter) but I have purposely scaled it back in an effort to ensure good wort quality...I'm @ about 85%.
Please share… how do you determine the volume of sparge water you’ll use (or do you?) and how do you determine when you’ll stop sparging? Do you pre-calculate your sparge water and drain the system dry? Do you just sparge until your pre-boil volume is reached, or do you measure the quality of the run-off and adjust w/ additional water or extract?

EDIT: Just caught your recent post. So it seems you pre-calculate your sparge water, add another 2 quarts, and fly-sparge slowly until the bed is dry, speeding up only at that last lap.

Do I got that right?
1 qt/lb with 8 lb malt is only 2 gallons of water. How are you getting 2.5 gallons run-off...especially since the grain wil absorb some of that 2 gal. of water you added?
If I drain completely, it’s 2 gallons in the mash, minus 1 gallon absorption (8 lbs x 0.125 gallons), plus 1.5 gallons under the FB. 2-1+1.5 = 2.5
But imo, the bottom line is: your system is not conducive to batch-sparging and is perfectly set-up for fly-sparging. So I would def fly-sparge.
Awesome, SCA! Thanks for the supporting words. That's the conclusion I've been heading towards, but it's good to know I'm not heading there alone.
 
Please share&#8230; how do you determine the volume of sparge water you&#8217;ll use (or do you?) and how do you determine when you&#8217;ll stop sparging? Do you pre-calculate your sparge water and drain the system dry? Do you just sparge until your pre-boil volume is reached, or do you measure the quality of the run-off and adjust w/ additional water or extract?
Using my spreadsheet I determine how much total water I'll need. After using my system enough I realized that 18 qt. sparge water was the 'magic' number (for most brews) that seemed to always yield good efficiency but did not over-sparge. So now I just subtract 18 qt. from that 'Total Water Required' number and viola...that's how much mash water I'll need.

I do drain the system dry but again...experience with my system has taught me to do the following: Just drain slowly until the wort level gets to the false bottom...then open the valve full-bore and drain everything out then shut the valve. Then if just I let the mash sit there and drip, drip, drip; I'll get almost exactly 2 quarts of 'last runnings' for use in yeast starters (this last 2 quarts does not go into the kettle). Then there is about 1.5 cups of cloudy stuff left in the lauter tun which gets thrown away.

I hit my volume and OG very close almost everytime. My final volume is almost always within 2 cups and the OG is almost always within 1 point with no 'adjustments' (i.e. adding water or DME/LME) along the way. I just start with a measured amount of grain, a calculated amount of water, a predicted efficiency; and everything just falls right into place...usually.;)
 
Using my spreadsheet I determine how much total water I'll need. After using my system enough I realized that 18 qt. sparge water was the 'magic' number (for most brews) that seemed to always yield good efficiency but did not over-sparge. So now I just subtract 18 qt. from that 'Total Water Required' number and viola...that's how much mash water I'll need.
Interesting... that's kind of working your numbers in reverse, isn't it?

You 'set' your sparge volume to 18 qt and let the formula determine the thickness of your mash. You don't miss getting to decide whether you want to mash thick or thin?
 
Interesting... that's kind of working your numbers in reverse, isn't it?

You 'set' your sparge volume to 18 qt and let the formula determine the thickness of your mash. You don't miss getting to decide whether you want to mash thick or thin?
Yea it is kinda reversed...i used to do it 'forwards' but after a while it just became easier to do it the way I am now. I don't miss getting to decide the thickness of the mash and hitting my volume/OG numbers consistently was more important to me. I adjust the fermentability of the wort by adjusting the temperature profile of the mash.

I also figure my hops in 'reverse'. First I figure out how much aroma I want and get an amount...then do the same for flavor hops...and then calculate how much bitterness I get from the flavor/aroma hops. Then it's easy to figure out how much hops I'll need for bitterness.

Sometimes reverse works.:)
 

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