[goscarletgry]

I have been brewing for over a year now and have decided to upgrade my all grain system. I went from having a 5 gallon cooler mash tun to now a 48qt 12 gal mash tun. I have made two batches on this mash tun and keep running into the same problem. When doing a 5gal batch in this 12 gal tun I leave 1-2 gal of wort in the tun. Is this tun too big for a 5 gal batch? Also I did not make a new manifold for this one yet. I just used the octagon manifold from my old round 5gal tun which only occupies half of the bottom of the tun. Would making a square manifold the occupies the entire bottom solve this?

Thanks

Mike K.

Dayton D.R.A.F.T. Home Brew Club

[tygo]

A 48qt cooler is not too big for a 5 gallon batch.  I'm using a 70 qt cooler for my 5 gallon batches.  No matter what you're going to lose some volume.  The standard "absorption" number is 0.12 gallons per lb.  With my system it's usually more like 0.15 gallons per lb.  Either way, for say a batch with 12 lbs or so of grain you're going to lose the 1-2 gallons that you mention.

[MrNate]

Not too big in my opinion. Copper manifold with slits on the bottom?

[euge]

It might be worthwhile to investigate John Palmer's work on this. He's done the leg-work.

My suspicions are that a new manifold is needed.

[BrewArk]

... I just used the octagon manifold from my old round 5gal tun which only occupies half of the bottom of the tun. Would making a square manifold the occupies the entire bottom solve this?

If you are fly sparging, I would definitely recommend a new manifold.  If you are batch sparging it's a little less important, but if you are having recovery problems, it's probably worth the $ to have a manifold that matches your system.  If your manifold is costing you wort w/every batch, it'll pay for itself quickly enough.

[ndcube]

How high off of the bottom of cooler is the outlet for the manifold?

[MrNate]

ndcube is on the right track. We need pictures.

Think about it, guys... 1-2 gallons? Why would ANY manifold in ANY cooler leave that much wort behind? Something's rotten in the state of Denmark.

[ndcube]

Just too add... If it's the same height in both coolers then the cooler with more surface area on the bottom is going to leave more behind.  (Unless you maintain a siphon)

[MrNate]

If it's a copper or cpvc manifold, which I'm guessing it is from the "octagonal" description, chances are he's siphoning. Unless he has it upside down. Which was my initial guess (cpvc, big tubes, upside down) but since he's dun gone I guess we don't get the satisfaction.

[Beertracker]

Q: Is this tun too big for a 5 gal batch?
A: No

Q: Would making a square manifold the occupies the entire bottom solve this?
A: Yes

Here's a design that I'm using on a similar sized mash-tun. I'm averaging 78% efficiency and leaving less than a quart of wort behind. *All CPVC construction w/ slotted bottom.  

 

[goscarletgry]

Sorry to the late reply to all your questions. The new tun is square 13"x13", my old 5 gal octagon manifold is only 8" in diameter made of cpvc. I bought some copper today and going to build a square manifold for the new tun. The old manifold was a great design and was very efficient.

[MrNate]

Am I crazy here? Why on earth would he need to build a new manifold in order to solve the stated problem? Why would a circular manifold cause the stated problem? How does making a square manifold solve the stated problem?

No? Just me?

Allright, I guess that's why I stuck to BrewHaHa.

[denny]

No? Just me?

Allright, I guess that's why I stuck to BrewHaHa.

Nope, not just you.  The problem seems to me to be a case of just not getting a siphon from the manifold.  The solution seems to be getting the manifold to sit lower in the tun.  That could involve a whole new manifold design, but it's doesn't necessarily seem like it has to.

[ndcube]

No? Just me?

Allright, I guess that's why I stuck to BrewHaHa.

Nope, not just you.  The problem seems to me to be a case of just not getting a siphon from the manifold.  The solution seems to be getting the manifold to sit lower in the tun.  That could involve a whole new manifold design, but it's doesn't necessarily seem like it has to.

I have the same thought.

[MrNate]

I guess the point being that it'd really suck to build a brand new manifold that ends up having the exact same problem because the real problem with the original manifold was never addressed.