False bottom and recirculation = efficiency problems?

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A_C

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I just moved and upgraded my system :), but now I am having efficiency issues :confused:. I'm using 3 keggles on a single tier with two pumps. I do constant HERMS-style recirculation and I fly sparge.

My false bottom in the MLT is high (there's 2.5 gallons of liquid under FB). To compensate, I add an extra 2.5 gallons to the mash (to get the desired thickness). But, to not overshoot my pre-boil level, I have to reduce the amount of sparge water accordingly. I am trying to figure out if this is causing issues. (Note: though my false bottom is high, I don't have a lot of dead space)

Concerns:
- liquid under false bottom isn't touching grains (but I do constant recirculation so shouldn't that make use of the liquid?)
- less sparge water may result in less lauter efficiency
- mainly, I'm worried that the false bottom and the constant recirculation are messing up my mash/efficiency somehow (my new toys are making my brewing more complicated :()

Do you see any problems here? If not, I may need to look elsewhere in the process. Thanks and I really appreciate any help
 
Yes, a more dilute mash will often lower efficiency. Why would you install a false bottom so high? To keep it above the bulkhead drain I'd imagine, but you'd typically run a diptube through the center to fix that problem.

What is your desired mash thickness that you add 2.5 gallons to?
 
Ya, my false bottom is above the bulkhead. I guess I could rig the false bottom to fit under the bulkhead then use a dip tube.

I have tried mashing at 1.25 qt/lb and 1.5 qt/lb (above the false bottom). As long as I don't mash with more water than I am targeting for pre-boil volume, I shouldn't be diluting my pre-boil gravity, right?
 
I've got a darn high false bottom in my mash tun, recirculate mash through my herms and fly sparge. I average 85% efficiency.
Depending on style, I'll use anywhere from 1.24 qt/lb - 2 qt/lb mash ratios. Doesn't effect my efficiency.
Are you getting channeling in your grain bed? You don't have to recirculate at max velocity, just a steady trickle while maintaining 1" or so of water over the grain bed is fine.
 
The more dilute your mash is, the less sparge you can process through it. That applies whether you fly or batch sparge.

You mentioned that you'd need to rig up a diptube if you moved the FB lower. You don't have one underneath the FB now? How is it that you have hardly any dead space without a diptube?
 
I do have a diptube under the false bottom. If I lowered the FB, I would have to rig it so the diptube could run through through the FB.

Thanks for the help
 
I do have a diptube under the false bottom. If I lowered the FB, I would have to rig it so the diptube could run through through the FB.

Thanks for the help

What about using something to fill up the dead space under the false bottom?

Maybe using a combination of steel nipples, couplings and plugs to make what is essentially a closed tube that is filled with water?

I've actually got a problem with my version of jkarp's Countertop Brutus 20 where it might be good to have something to take up space in the kettle - maybe something like the closed tube setup like the above, but using larger pipe sizes like 2 inch fittings.

Question is ... will an enclosed water-filled arrangement be safe if heated to boiling point or the pressure build up make it a potential bomb?

I would actually use it at mashing/mashout temperatures only.
 
I would not build a closed tube to fill dead space under the false bottom. Unless you own the pipe and fittings, you are going to spend more than buying/building a diptube.
 
I have a similar issue on my brand new recirculation system. What I found was that you really need to let the grain bed settle for 10-15 minutes after dough-in before you kick on your pump. That way the grains settle homogeneously and you get even flow through the grain bed. If you kick on the pump immediately, that heavy flow of liquid pushes the grains out of the way and forces channeling to happen.
 
I have the same problem to a certain extent. I believe it all comes down to having less sparge water available to rinse the grains. Sometime I will get around to modifying the FB base so it sits lower.
 
I have the same issues and I just changed to batch sparging today and hit 9% higher on efficiency (79%) on the first try . Try that, I was amazed. I am sure my system wasn't right for continuous sparge
 
I had similar issues.

I have a Pico style false bottom installed in keggle with diptube. It takes 2.5 gallons of liquid to reach the false bottom.

I also use a constant recirc. mash system and fly sparge.

Started off around 60% efficiency and changed the following to now achieve around 76-78%.

1) Crush grain myself to a bit finer than LHBS's
2) Thicken my mash to no greater than 1 qt/pound of grain. This lets me add about a gallon more to my sparge water volume. (I was at 1.5 qt/# ratio before changing to ~1 qt/#)

Say I have 10 pounds of grain for my recipe, my mash water will be 10 quarts of water, plus the 2.5 gallons it takes me to reach the false bottom. So Ill be recirculating a total of 5 gallons of "mash" water, but only 2.5 gallons of water is in contact with the grain.....:drunk:

3) Sparge slllloooooooooowwwww, very slow! With the smaller volume of sparge water we are able to use, its helped me to sparge as slow as I possibly can. I heat my sparge water to about 172-174 to account for some heat loss in tubing/transfer. Prior to sparge I raise mash temp to 168 and hold for 10 mins.
My average sparge volume is 4 gallons and I try to stretch that 4 gallons over at least 25 mins. with the goal being 10 mins for each gallon of sparge water.

This has helped me reach and exceed my efficiency target the last 2 batches.

Also, take a look to make sure that you aren't over calculating how much wort loss your system "produces." Even a half gallon of wort left behind can dock you a few percentage points.

Hope this helps you somewhat!

:mug:
 
I have a Pico style false bottom installed in keggle with diptube. It takes 2.5 gallons of liquid to reach the false bottom.

I have the same false bottom with a bottom drain. I already trimmed the supports a bit and now have 2 gallons bellow the FB. I will probably try and get that to 1 to 1.5. This seems to be more of an issue with a 5 Gal batch.
 
I have the same false bottom with a bottom drain. I already trimmed the supports a bit and now have 2 gallons bellow the FB. I will probably try and get that to 1 to 1.5. This seems to be more of an issue with a 5 Gal batch.

Agree 100% with you on the 5 gal batch size being biggest contributor to efficiency woes (with our style false bottom).

Not enough liquid to go around with that large of a "dead" space in a 5 gal batch.

Just gotta get creative with ways to make it work with 5 gallon batches but it can be done.

What is your average efficiency?

I liked the idea I saw in an earlier post in this thread about submerging objects in the gap to help lower the volume of water needed to reach the false bottom. I just cant think of what would work well?
 
I am getting 78 to 80 percent brewhouse efficiency and 83% mash efficiency. When I build this system I thought I could get up to 90% brewhouse, so I will keep working on it up to a point. This system is still fairly new with 6 batches through it. One place to look for me is my mill setting. When I implemented the new system I widened the gap on my mill because I didn't really know how it would react with constant recirculation. Once I get the FB set how I like it I will start tightening the gap until I have problems and then back off a bit. Hopefully I have everything set in a couple of months.
 
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