MLT manifold mod and Resolution Oatmeal Stout

My ideal brew day is relaxed, moving at a slow and methodical pace, with plenty of beer. My last brew day was nothing like that. It was a hellish struggle that made me question why I choose to subject myself to this 'hobby'. So with that in mind, I spent quite a bit of time researching manifold-based mash tuns and making modifications to my own to avoid any chance of another stuck sparge. For those new to all grain brewing, I'll direct you to Palmer for a crash course in lautering techniques. 

 For reference, I am currently mashing in a 48 quart Coleman rectangular cooler. I used many of the countless DIY threads and videos to retrofit a metal outlet valve through the drainage port at the bottom of the cooler. This process seems fairly standard amongst all improvised mash/lauter tuns (MLTs); the innovation and variation comes in how you separate the wort from the spent grains. As I've chosen to do batch sparging, I would argue that a manifold system (which is cheap and easy to build) has all the merits of a false bottom. The argument here is that channeling is not relevant in batch sparging the way it is in fly sparging. Really with batch sparging, the most important thing is to get every drop of wort out that you can.

I built a manifold using CPVC and a dremel. Make sure you use CPVC rather than PVC. CPVC is designed for use with potable water at temps approaching 200F, so it is compatible with brewing. You can see the design in the pictures below. I think the only change I'd like to make is to swap the 3-way 't' piece at the outlet valve for a 4-way, allowing for better drainage. Would have grabbed one initially but all my local hardware stores don't carry the 4-way piece. There's roughly a 1/2" of dead space at the bottom of the cooler that I should try to remove at some point. I initially made the cuts for each segment of CPVC using a serrated Ikea bread knife, but it's a really exhausting process. My initial slots were about 1 mm wide, and cut roughly a quarter to a third through the diameter of the pipe (not much uniformity when using the bread knife). I put a slit roughly once per 1/2" along the pipe. 

This initial design may may have been suitable for successful brewing -- I will never know. But if you're going to use a manifold, I can't emphasize enough, face the slits downward in your tun. This may have been my only problem with the setup that caused the disastrous stuck sparge on my last brew day. I wanted to make absolutely sure it wouldn't happen again, so I made some modifications. I increased the slit density to one slit per 1/4", and used a dremel to widen the slits to about 3 mm. The slits also go more than half way through the pipe now. If I were to do it again, I'd probably leave the slits shallower so that the pieces were a bit stronger. I have to be careful not to bend them now.  I also went out and bought a fine, voile dry-hopping/boiling bag from my LHBS to cover the manifold. I actually brought the manifold to the store and played with a few bags until I found the one I wanted. It fits as if it were designed specifically for the manifold. I simply tie it off at the outlet, and now I have two lines of defense against a stuck sparge. 

Manifold with modifications

Putting the bag on the manifold

Manifold added to the tun

With the modifications complete, I wanted to brew something fairly simple to test it out.  I decided to make an oatmeal stout as I've been on a dark beer kick recently. At this point, I hadn't tried my Frustration Black IPA yet, so when I bought the ingredients for this beer (and for a coffee porter I'll be brewing soon) I was once again pretty heavy-handed with the roasted grains. Should have used a lot more oatmeal, probably. I also wanted to mash pretty high to leave some dextrines in there for body. 

I used dry yeast for this one following the  K.I.S.S mantra. I've been reading a decent bit on the differences between dry and liquid yeasts and trying to formulate an modus operandi for choosing yeasts. Dry yeast is definitely easier to work with and more viable out of package (no starter or forethought necessary). However, the drying process is only compatible with a few types of yeast. Currently my opinion is that dry yeast is a good option for beers that do not require or highlight particular flavors from the yeast. Liquid is definitely the way to go for some of the more in your face yeast flavors (e.g. Belgian beers, ester-y English beers, German hefeweizens, etc). 

Resolution Oatmeal Stout

Grain bill

US 2-row: 6 lbs (%)

Oatmeal: 0.75 lbs (%)

Black patent malt: 0.25 lbs (%)

Chocolate malt: 0.5 lbs (%)

Roasted barley: 0.5 lbs (%)

Single infusion mash @ 149F for 90 minutes

Yeast

Fermentis Safale US-05 (one 11.5 g packet, rehydrated)

Hop Schedule
Willamette (5.0% AA): 0.75 oz, 60 min
East Kent Goldings (6.4% AA): 0.25 oz, 20 min
Willamette (5.0% AA): 0.25 oz, 20 min

Stats

SRM color: 40+
IBU: 32
OG: 1.052
Brew house efficiency: 63%
Batch size: 3.5 gal

Timeline

Brewed on 1/1/2014
Bottled on 1/26/2014
Tasting on 3/28/3014

Brewing notes

For this brew, I actually had a friend over to hang out and drink, despite the fact that it was New Year's day. The day was so relaxed, and so different from the last time around that I actually got a bit sloppy with some of the timing. I heated the strike water 10F above my strike temp and added it to the tun to preheat it as it dropped to my desired strike temp. I wasn't being diligent in checking it, however, and I dropped a few degrees too low. Rather than doing the intelligent thing and adding some boiling water to get back up to the ideal temperature, I doughed in anyway. The actual mash temperature was at about 149F at the start (I was aiming for 156F). I didn't measure the temperature at the end of the mash (I intend to investigate heat loss in my next brew). As a result of the lower mash temp, I extended the mash to 90 minutes to compensate -- making sure beta amylase had plenty of time to do it's thing. I'm anticipating that this brew will end up being a very dry stout as opposed to the sweeter stout I wanted. Oh well, live and learn.