MT to LT - how big a valve for gravity transfer?

[brewjedi]

Does anyone have experience with gravity transfer from MT to LT. I was thinking 1" valve on the side of the MT at the bottom would be easy enough to install and big enough to gravity feed but I was hoping someone had some actual experience transferring mash via gravity feed. I Built a 4 tier stand with MT and HLT on top, LT below that, BK below that and fermenter on the floor.
Why do I want to do this you ask? I want to stop scooping mash. Also want to eliminate the theoretical chance of "hot side aeration". Since I started step mashing and mashing off in a dedicated MT with float controlled fly sparge I've seen efficiency go through the roof. Protein rest makes for "good head"(chuckle) and no chill haze. My LT has a bad ass manifold I can practically lauter flour without getting stuck. Also, I can set up a new batch after transfer and start mashing while I lauter. Kind of cool being able to brew 2 or 3 ten gallon batches in 1 day.

So any suggestions?

[dunleav1]

Does anyone have experience with gravity transfer from MT to LT. I was thinking 1" valve on the side of the MT at the bottom would be easy enough to install and big enough to gravity feed but I was hoping someone had some actual experience transferring mash via gravity feed. I Built a 4 tier stand with MT and HLT on top, LT below that, BK below that and fermenter on the floor.
Why do I want to do this you ask? I want to stop scooping mash. Also want to eliminate the theoretical chance of "hot side aeration". Since I started step mashing and mashing off in a dedicated MT with float controlled fly sparge I've seen efficiency go through the roof. Protein rest makes for "good head"(chuckle) and no chill haze. My LT has a bad ass manifold I can practically lauter flour without getting stuck. Also, I can set up a new batch after transfer and start mashing while I lauter. Kind of cool being able to brew 2 or 3 ten gallon batches in 1 day.

So any suggestions?

Just remember it's the girth, not the length.

[Ozwald]

Depends on the thickness of the mash. I typically use 1.4 on my system & I can guarantee that wouldn't pass through a 1" ball valve without issue every time. I have 1" valves on the bottom of my conicals & a thick yeast slurry can be a problem if you let it compact enough. I would think 3"+ to be on the safe side. I can't imagine trying to unplug a ball valve of a 170 mash above eye level being very fun or safe.

[brewjedi]

well, I installed the 1 1/4 valve and it worked. I didn't drain out the last 2.5 gallons out of 12, but that was easy enough to dump. So I figure 1 1/2 valve would get the job done...