Tag Archives: cooler

Duck-in Cooler Update

Hello loyal readers (and others),

I started the duck-in fermentation cooler project with the goal of keeping my homebrew at a temperature appropriate for fermenting. It is mostly finished now and stands in the brew-room of my new house undergoing light testing.

On the left is my 15-gallon fermenter with about 12 gallons of tap water and a thermometer probe. To see how long this contraption takes to get to temperature I started running the AC at about ten in the morning yesterday. Here is what the thermometer said:

Top is ambient temperature and bottom is the water. Yep, it comes out of the tap that warm, which makes for problematic wort chilling. After 8 hours the water temperature dropped to the low seventies. At the 12 hour mark it was in the mid sixties where it stayed mostly constant. Most ales are happy in this range, so I am happy. The ambient temperature was in the high seventies. Initial tests showed that it could hold 65-ish° without a full fermenter even in 90° F weather, giving me a 25° drop under ambient. I am using the AC’s built-in thermostat, which probably doesn’t go much lower than 65. I measured 40° air coming out of the unit, so with the right controller I could get down lower.

I do not know how efficient it is. When the cooler is in full swing I felt around all the likely places where cold might escape and only found one. I would like to purchase a watt-hour meter to see how much electricity this thing needs. The total cost of the cooler comes in at around $380 for materials; my time is more precious, but who’s counting?

The cooler appears to be ready for a maiden fermentation, but I have not decided what to make. There is space for two 15-gallon fermenters and four corny kegs, so I have the capacity to make a respectable amount of beer.

Here is Proof My Wife Loves Me and Wants Me To Be Happy

With apologies to Ben Franklin.

My last beer fermented a little too warm and turned out full of esters. What I am calling The Fruity Brit is still drinkable as demonstrated last night when Adie and I had eight friends over for pizza and beer. The first keg is at least three gallons light. A good time was had by all, even without chairs.

The Fruity Brit is light on hops and body. I can pretend there is a clean malt profile, but the fermentation flaws overpower that. However, I hit the alcohol content right on the button: non-offensive. The Brit’s gravity bottomed out at 4° brix falling from 6°, putting it at about 2.3% ABV. Next time I will start and end higher, and throw in more hops for good measure. My objective is to zero in on a medium-bodied, lightly hopped British session beer.

While gatherings of friends will continue, I do not anticipate unaided fermentations to turn out any better. As summer approaches, Texas ain’t getting cooler. In Redwood City I had a chest freezer with good control over bubbling carboys, but now I have fifteen gallon conicals towering four feet tall on PVC stands. Such things just do not fit in this sort of chest freezer. A proper stand-up freezer runs around $500 and Craig’s List here is pretty pathetic. Those stand-up freezers only fit one of my fermenters, but I expect to be brewing with increasing frequency.

Three weeks ago I started working on a walk-in cooler that could accommodate both my fifteen gallon conicals. Many entwined brewers might meet steep resistance from their significant others, but my beautiful wife simply smiled and told me what a great idea it was. My initial estimate for materials was two hundred dollars easy, but I will probably go over by around fifty percent. While I may get a grimace from Sweetie, I know she will support me. It makes me all warm and fuzzy thinking of how much she must love me.

To drive the cooler I have a window air conditioner (which I wanted to leave in Cali, but Adrienne insisted we keep it; how smart). Here is how my cooler starts; left to right, the frame for the bottom and top.

Basic dimensions are 4×2 and 5 feet high. The skeleton is mostly finished 2×2 furring strips with a few 2×4 studs in key places. Here it stands loose fit together.

For insulation I am using reflective bubble wrap insulation stapled to the exterior plywood:

Followed by loose-fill insulation.

Then a semi-rigid plastic interior layer glued and stapled to the frame (see below). The floor gets a layer of plywood under the plastic to support the weight of the fermenting beer. Here is a shot of the bottom corner, the frame nailed to the floor.

Today a friend, Clay, and I made a lot of progress on the cooler. He is an electrician and offered to wire up an outlet, switch and light fixture. With these features, the project goes to way-cool.

Here is the back. The large opening is the AC mount. Clay is putting the light switch in center-top in our make-shift wiring box. All of the standard-type electrical bits and bobs are made for 2×4 studs while my walls are one and three-quarters thick, so we have to be creative.

Here is Clay again working on the light fixture. It is slightly too deep for the ceiling so we shimmed it out, taking advantage of the flexible plastic to hide the protrusion. We filled this with insulation and covered in plywood.

I will get some pictures of the interior up soon. When it is done I will break down the cost of materials. Expect a second follow-up when the thing is working.

In parting, I would like to thank Adrienne for allowing this project to take up my time, our money and her “pretty living room” for three weeks, going on six. I love you sweetie.