Whirlpool placement for BIAB and recirculating?

[kurds_2408]

I currently biab in a cooler with propane burner and kettle. Been wanting to upgrade to eBIAB for a while and thinking of taking advantage of Black Friday to start a diy build. I’m planning to build something similar to a BrewHardware setup with some tweaks. I am planning to recirculate over the top and through the whirlpool port during mash. The kettles I’m looking at mostly have the the whirlpool port 1/3 to 1/2 way up, but most prebuilt eBIAB systems have it lower, near the bottom. I am worried about the bag twisting up with the port being higher. Does it need to be below the false bottom to prevent this? Does anyone have experience recirculating through a higher whirlpool with a bag?

 

[stamandster]

Just use the drain port for the recirculation, unless there isn't one. You want the bottom most wort otherwise you will cause stratification of the starches/sugars/enzymes/temps.

 

[kurds_2408]

Just use the drain port for the recirculation, unless there isn't one. You want the bottom most wort otherwise you will cause stratification of the starches/sugars/enzymes/temps.

I plan to have the wort to come out through the drain, then through a “T” and go in through both the whirlpool and on top of the grain.

 

[stamandster]

You just want it to go from the top, nix the side whirlpool

 

[doug293cz]

You just want it to go from the top, nix the side whirlpool

I agree, unless you are going to have a "malt pipe (solid sided basket)" as part of your system. With just a properly sized bag (you should be able to put the mash vessel inside the bag - just barely, with excess at the top) there will be no gap between the bag and vessel during the mash, so recirc from the top is all you need.

On the other hand, with a malt pipe, you have stagnant water between the malt pipe and vessel wall, and if this stagnant volume is not homogenized with the bulk of the wort, then you suffer lauter efficiency reduction. For the malt pipe case, directing some of the mash recirculation into the gap between the pipe and vessel is beneficial (although there are other ways to insure proper homogenization prior to lautering.)

Brew on

 

[stamandster]

I'd be curious for anyone who has a malt pipe type BIAB to provide their empirical evidence that a mid-way return assists with homogenization to a mash bed within a malt-pipe (the mid-way return can't actually interact with).

I would predict that fluid dynamics would net us a slightly different story regarding the liquid between the malt pipe and the wall of the container. If you have a pump pulling liquid from the bottom, it's more than likely going to pull liquid from the less resistant area (side wall) and than the more resistant area (malt pipe/mash bed). So, adding a secondary mid-way input would just be circulating the liquid mid-way slightly faster. Of course my educated assumptions could definitely be wrong! @doug293cz If you have any sources for this, that would be great to add!

 

[Bobby_M]

I'd be curious for anyone who has a malt pipe type BIAB to provide their empirical evidence that a mid-way return assists with homogenization to a mash bed within a malt-pipe (the mid-way return can't actually interact with).

I would predict that fluid dynamics would net us a slightly different story regarding the liquid between the malt pipe and the wall of the container. If you have a pump pulling liquid from the bottom, it's more than likely going to pull liquid from the less resistant area (side wall) and than the more resistant area (malt pipe/mash bed). So, adding a secondary mid-way input would just be circulating the liquid mid-way slightly faster. Of course my educated assumptions could definitely be wrong! @doug293cz If you have any sources for this, that would be great to add!

Been there and done that a while ago. By the way, there is no way the liquid on the sides of a malt pipe is going to flow downward because the recirculation wort is not filling that space. When I put 4 probes of my temp logger in various spots in a basket type system, the coldest spot was the liquor between the basket and sidewall of the kettle, by up to 7F. Heat is leaving the kettle through the sidewall and liquor recirculated to the top and into the basket does nothing to heat it other than radiating through the basket (slowly). The delta is a little better in double wall systems and worse in single wall for obvious reasons.

Stirring the heated zone below the bag (via an appropriately placed whirlpool return) resulted in about a 1F delta across the whole system during single temp rests. In the case of a narrow basket design, tilting the whirlpool up at a 45 degree angle gets that whole dead zone to exchange with the heated liquor below resulting in a much more stable grainbed. I put this article together to illustrate it a little more. https://www.brewhardware.com/category_s/1972.htm

 

[Bobby_M]

I plan to have the wort to come out through the drain, then through a “T” and go in through both the whirlpool and on top of the grain.

Ejecting the whirlpool liquor directly into the side of the bag is not going to provide any of the benefit that I posit on the split flow design. It should go below the false bottom or at the very least, have the outlet of the whirlpool tube firing the liquid into the false bottom at a 45 degree angle because the bag won't impede it in that case.

If you can't have the kettle built that way for some reason, you can forgo the whirlpool but insulate the heck out of the vessel externally.

 

[kurds_2408]

Ejecting the whirlpool liquor directly into the side of the bag is not going to provide any of the benefit that I posit on the split flow design. It should go below the false bottom or at the very least, have the outlet of the whirlpool tube firing the liquid into the false bottom at a 45 degree angle because the bag won't impede it in that case.

If you can't have the kettle built that way for some reason, you can forgo the whirlpool but insulate the heck out of the vessel externally.

Thanks Bobby. I was hoping to hear from you. I’ve been debating back and forth between getting one of your systems or building my own copy with parts I already own and stuff from my LHBS. My LHBS has a smoking good deal on some floor model kettles, but they all have the whirlpool higher than you put yours. They are TC ports though. So like you said, do you think as long as I point the tube at a 45 it will be fine?

I am also considering flipping a sanke keg I already have upside down for a custom bottom drain. Obviously doing that I could put ports wherever I want.

 

[Bobby_M]

Thanks Bobby. I was hoping to hear from you. I’ve been debating back and forth between getting one of your systems or building my own copy with parts I already own and stuff from my LHBS. My LHBS has a smoking good deal on some floor model kettles, but they all have the whirlpool higher than you put yours. They are TC ports though. So like you said, do you think as long as I point the tube at a 45 it will be fine?

If the whirlpool port isn't extremely high, it's fine. For example the Spike+ kettle has it only a couple inches above where the mesh FB sits so if you use the rotating TC whirlpool, (Spike calls it the SIDE PICKUP), it extends low enough to fire into the bottom past the bag.

 

[CascadesBrewer]

I put this article together to illustrate it a little more. https://www.brewhardware.com/category_s/1972.htm

Not directly related to the OPs question, but I do wonder if there are any ideas on improving the circulation for the typical all-in-one basket systems.

The issue I noticed on my first run of my Foundry (not using recirculation) was that the water on the outside of the basket was significantly hotter than the grain & water in the basket. It never mixed with the cooler grains. I heated the water up to around 159F to target a 152F mash. In the basket cooled to around 149F and the outside was around 155F. A friend gave me his old pump, so I have used recirculation for the last two batches, but the dead space around the basket bugs me. I could ditch the basket and just use a bag and false bottom, but it is easier to lift and drain the basket in the house without making a mess.

 

[Bobby_M]

Part of the issue with the AIO baskets is that the column of grain is really tall and the liquid can't flow out the bottom fast enough to turn over. The main reason that the liquid on the sides of the basket, and the associated heat, was not integrating with the colder grain is stagnation. It needs to be moving a bit to transfer heat. The way I build a standard kettle is pretty obvious, the stirring under the bag helps distribute heat where it's created and measured. In an AIO, the split flow would also be beneficial as the pump has way more capacity than the grainbed and malt pipe filter can flow. Since the boiler is so tall and the space between the malt pipe and boiler is so thin, that stirring would likely be best over the top or if it's through the sidewall, mounted up higher.

 

[Willy]

At one time I used to put the bag inside the tall malt pipe on the Brewzilla Gen 4 ... But had issues as discussed above with temp and also not draining fast enough to properly recirculate during a mash.

I tried a batch just using the Wilser bag without the malt pipe. No question about it... The mash went smoother, drained efficiently (especially compared to using the malt pipe/BIAB).

I have no plans on using the malt pipe with a bag. Brewing works much better with just a good bag - without the malt pipe on a Brewzilla 35L.

Anyone else do the same on a Brewzilla?