Cold Brewed Beer

04 Jan 2014

It’s not what it sounds like. No, it was the brewer who was cold. The temperatures outside today ranged from 6°F to 20°F during my brewday. It’s a challenge to keep things from freezing at those temperatures, especially the water supply for the chiller. While I was at it, I re-learned how awesome polypropylene long johns are when I spilled a gallon or so of rinse water on my jeans and barely noticed it for the next hour.

But enough gloating. During the mash, the postman showed up with the fittings I ordered for the March pump I found under the tree this year. I spent a little extra to build a system I’ll be happy with:

Indeed, I am very happy with the result - everything worked beautifully. My complements to Bobby Mierzejewski at BrewHardware for an extremely well-designed selection of, well, brew hardware.


The cam-locks come male and female varieties, and typically the female ends are attached to hoses. The wort connections on my plate chiler are ½” barbs, so I elected to make the chiller a permanent part of one of my hoses. So I have one 10’ hose with a female cam-lock on each end, and one 10’ hose with a female cam-lock on one end and the wort chiller on the other. The other side of the chiller connects to a shorter (3’) length of hose followed by another cam-lock.

Although silicone is stable at boiling temperatures, it does get soft, and with the weight of a full hose behind it, this can cause kinking around sharp bends where a hose attaches horizontally. The recommended fix is to use the BL model cam-locks, which incorporate a 90° elbow, allowing the hose to hang from the fitting. I chose to put one BL on each hose, with a Big C on the other end. On the hose with the chiller, the BL is on the longer end. This arrangement worked fine today, but I may eventually upgrade to BL’s everywhere.

Beer pumps use a magnetic drive similar to a stir plate, so while they only run at one speed, the flow rate can be adjusted by restricting the output. The impeller just skips a few magnetic notches, with no harm to the mechanism. The input needs to be left clear, though, since the pump is not self-priming and requires a steady supply of fluid to continue operating. I purchased a nice 3-piece full-port valve for the outlet. 3-piece means that the valve can be disaassembled as needed for cleaning, and full-port means that when open it allows a flull ½” flow. The cost difference over less fancy valves was minimal.

The particular model of pump I have, the March 809-PL-HS-C, has a ¾” MPT inlet, presumably to allow maximum inlet flow. The cam-locks are only ½” NPT, so I got a ¾” to ½” reducing coupling.

Both ends of the pump, and the brew kettle (which already had its own valve), are fitted with male cam-locks (type F). I also purchased a garden-hose adapter and an extra F cam-lock so that, in warmer weather at least, I can flush the system with a garden hose.


Someday, I hope to use this pump to recirculate a mash. For today, though, I only used it to chill the wort. Here’s how that worked.

The setup looks like this: One hose runs between the brew kettle and the pump inlet, with the BL cam-lock on the kettle. The hose with the chiller inline is attached to the outlet of the pump, and the other end dangles back into the brew kettle. Someday I’ll have a whirlpool port with a cam-lock on it, but until then dangling works fine – in fact, the weight of the fitting helps keep the hose from slipping out of the kettle.

The pump is not self-priming, so it needs to be filled with fluid by gravity before it’s started, so the pump must be well below the outlet of the kettle. The idea is to open the outlet valve on the pump, open the valve on the brew kettle, and let wort run downhill to the pump. This proved a little more difficult than I expected, as large air bubbles sat stubbornly in the tubing. Likely part of the problem is that 10’ hoses are longer than I need. The priming technique that seemed most successful was to start at the pump and “walk” the air bubbles back to the kettle by holding a loop of the hose above the kettle level. Once the bubbles reach the kettle valve, they “burp” into the wort and the hose is full of fluid.

With all this set up, in the waning minutes of the boil, begin recirculating wort without running cold water through the chiller. The effect is to further sanitize the system with the boiling-hot wort. Once the flame is out, begin the flow of cooling water. Continue recirculating until the wort reaches pitching temperature. Once that’s complete, the pump can easily move the wort to the fermenter by simply redirecting the output hose into the fermenter. I found this a little awkward, as I was using a Better Bottle and thus had to hold the cam-lock over the mouth for the duration. It might be nice to bulid a filler wand of some sort with a male cam-lock on it.

Once the kettle is empty, there’s still about a liter of sweet wort in the hose, pump, and chiller. I attempted to reduce the significance of any loss here by adding my top-up water to the kettle and pumping it through, but it’s still important to get every bit of sugar into the fermenter. The technique is pretty basic: unplug the cam-lock at the kettle and hold the hose up high until the wort drains out of it completely. Then hold the pump up until air appears at the outlet, then disconnect the cam-lock at the outlet and continue draining the chiller and attached hoses. This would have been a lot easier if one hand wasn’t occupied pointing the hose into the fermenter!

Finally, the pump can clean itself and the chiller. The idea is to first forward-flush things, then reverse the connections to the chiller and back-flush it. This should free up any stubborn bits of trub.

Once that’s complete, pump or run some sanitizer through the chiller and pump, then dry them out as well as possible.