Cooler MLT recirculation / vorlauf port through lid - need advice
 

I'm looking to create a recirculation port through the lid of my cooler MLT so I can vorlauf for the last 15 min. of my mash without opening up the lid of the cooler. I use a pump and now need to open up the lid letting heat escape to stick the hose in there. The general idea is to have a quick connection on top of the lid and a barb under the lid that I attach some tubing to so I can lay it on top of the mash in a semi coil to gently return the wort. I'm looking for some advice on the parts to make this happen, specifically, the parts needed to go through the lid and secure it well as well as any overall advice / insight. Here's what I'm thinking:

Overall needs:

• Weldless (of course) way to get through the lid
• Doesn't need to be watertight, but should be tight so as to minimize heat loss
• Ideally be able to spin / swivel it a bit so the intake faces the direction I want after I screw the lid on
• Valve would be a nice to have to throttle speed at the MLT rather than bending down to the pump, but not necessary
• Return to mash should be relatively gentle so as not to disturb the mash bed being set on the false bottom
• Would be nice to be able to open lid with pump running to see clarity of return - nice but not needed - see spin comment above
• Way to "seal" off the hole to minimize heat escaping during the mash

Parts I think I need:
Intake

• 1/2" NPT Male quick disconnect plug
• 1/2" x 1/2" NPT 90* elbow

Middle portion through lid

• 1/2" NPT x 1/2" NPT nipple
• (2) 1/2" NPT washers
• (2) O-rings - optional I'm guessing since I don't need it water tight, but might be good to help insulate

Return

• 1/2" NPT 45* or 90* elbow??? - might be good to have to help direct the flow and hose to better coil and lay on the mash
• 1/2" NPT male x 1/2" barb - silicone hose attaches to this
• hose clamp - like the ones used for racking canes to stop flow so heat doesn't escape up and out the tubing during the mash.

Questions:

1. How do I properly figure out the length of nipple I need? I'm not sure how these are sold (ie. by overall length or by the length of the "unthreaded dead space" between the threads)
2. Do you think the 45* or 90* return would be better?
3. Any other insight / ideas to improve upon this?

** sorry for the turned picture, wasn't sure how to spin that right side up

Thanks!

I think the best way to do it would be to use a rotating garden sprinkler head underneath your lid. If you could find one for cheap enough, you could use a 1 or 2 inch pipe nipple and attach the sprinkler head to the end on the inside. You would be able to take the lid off, but you would have to hold the lid directly above the mash tun.

The size of the pipe nipple will depend on the lid thickness, of course. Get a couple of washers and a couple of rubber seals that will fit the pipe nipple and put one washer and one rubber seal on each side of the lid to start with. Screw your female barbed end on the outside until you get a tight fit. If the pipe nipple is too long and you aren't getting a good fit, just add more washers until you do.

This should work with the sprinkler head, depending on the speed of the liquid flowing through. I know that sprinklers aren't food safe, but I don't think that the hot wort would mess anything up or pick up any off flavors.

Good luck!

Here is a photo tutorial
Because it's so low pressure you don't even have to sweat (solder) the fittings.

Cheers!

Gotcha - thanks guys! So essentially I'm building a sparge arm. Hadn't really thought of it that way since I batch sparge, but makes sense. Thanks for the pics - very helpful!

I use this:

https://lh4.googleusercontent.com/-H.../short_arm.JPG

On the top of the lid is a 90* elbow with a male camlock fitting. It screws to a barb on the inside of the lid. Then I have two sparge arms for my system. The short one shown is for either 10 gal batches or high gravity 5 gal batches. I have one with a longer piece of tubing for low gravity 5 gal batches. Total cost is something like 20 bucks (if that).

YUP! That's exactly what I have on my HERMS (or soon to be) setup and while it mashes it will be circulating the water through just like a vorlauf and then when it's time to sparge I just hook the pump up to the sparge water. Good luck

ps- I made mine out of CPVC based on some designs I found here on on the forum

So, with the cooler lid in place, how do you assure you're maintaining the fluid level above the grain bed?

Cheers!

During recirc there's no change. During sparge I would occasionally peek. I also used a gate valve instead of a ball valve to better control flow.

What I did was drill a hole in the lid. Then I took one of those aluminum brownie pans, and poked a ton of holes in it with a nail. I took that and screwed it onto the inside of the cooler lid, right under the hole I drilled. When I'm sparging, I just stick the hose in the hole, and it is dispersed over the mash bed. It cost me nothing, because I already had the Al pan. YMMV. Good luck.

Yea making sure it is the right level is a problem without peeking. I have seen some people put a float shut-off valve so when it goes too low it open the water valve, but like OneHoppyGuy said you don't have to worry about that unless your going to sparge with it.