recirculating wort chiller

RECIRCULATINGWORT CHILLER

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iven that there are so manyplaces in the world wherefresh, potable water is a

scarcity, my personal philosophy isthat the least we can do as enthusiastsof a water-intensive hobby is minimizewater usage while brewing. One obvi-ous place to start looking for waterusage inefficiencies is the wort chilling process. This chiller project, which turns a

typical immersion chiller (the biggestoffender in terms of waste water) intoa water-recirculating chiller, can be abig help in warmer climates withwarm ground water, and is also usefulfor reducing water usage.

I’ve been using a plate chiller forsome time, which is efficient in termsof water consumption. However, Ihad growing concerns about properlysanitizing homebrew-sized platechillers, and I started looking for analternative. In my search, I admired avery clever pump-driven “whirlpool”chiller design by BYO contributorJamil Zainasheff, but I didn’t like theidea part of the design, which requiredpumping the wort around for 15 min-

utes while it’s still hot. Instead, I con-sidered recirculating the chilling waterinstead of the wort, a design changethat would save a lot of water whileusing a cheap pump. This project is a similar concept to

using ice banks, which have been usedin larger breweries for years. In thesesystems, cold water or glycol is frozenin large reservoir tanks. This allowsthe breweries to even out the coolingload and have much smaller compres-sors, saving money. This recirculating chiller project is

built on three main components: asubmersible or in-line pump, a stan-dard coiled-copper immersion chiller,

and a cold water reservoir (a plasticbucket or cooler). The reservoir isfilled with water and ice. The pump issubmersed in the reservoir and theother end is attached to the input sideof the immersion chiller (which sits inthe kettle, as normal). The output sideof the immersion chiller is connectedvia tubing back to the reservoir, com-pleting the circuit. It is simple to use,efficiently chills — and is great for sav-ing water!

Story and photos by Forrest Whitesides

Recirculating Wort Chiller

g

Parts and Tools

• A standard coiled-copper

immersion chiller

• A cold water reservoir (plastic

bucket or cooler)

• Submersible pump, such as a

March model 809 impeller

pump

• 2 to 4 feet of 1⁄2-inch food-

safe, heat resistant vinyl tubing

• 3⁄8-inch brass hose fittings

(depending on your chiller),

including a female NPT hose

barb fitting

““““This project is a similar concept to using ice banks, whichhave been used in larger breweries for years. In these systems,cold water or glycol is frozen in large reservoir tanks.


1: ASSEMBLE THE PARTSOther than a decent pump, all you need for this project isan immersion chiller, either a bucket or cooler (5-gallon/19-L capacity works fine), some vinyl tubing, and a few brassplumbing fittings to help connect everything. The mostcommon type of immersion chiller is made from 3⁄8-inchcopper tubing, but 1⁄2-inch copper will work as well.

2: PUMP SELECTIONIf you already have a March model 809 impeller pump (asmany homebrewers do), you can skip to the next section. You need a pump that has an operating head pressure

rating that exceeds that of the total head pressure exertedby the recirculating system itself (read on for a method toestimate system head pressure). This rating is given ininches or feet of head pressure, which in the broadestsense is any resistance exerted on the pump, be it gravityor other flow impediments like small-diameter system tub-ing, also known as friction loss. Head pressure is not justhow high the fluid must be pumped and includes severalother factors (read on). Head pressure is just as importantas flow rate when selecting a pump.To arrive at the approximate operating head pressure of

your system, use this formula: System Head Pressure = A+ (B / 10) + (C / 2) + (D / 4), where “A” is the verticalheight in feet between the water level in the reservoir andthe input connection of the chiller, “B” is the total distancein feet of the system (vinyl tubing plus chiller coils), “C” isthe number of 90-degree bends in the system, and “D” isthe number of miscellaneous adapters and plumbing fit-tings. All of those things are a factor in how much resis-tance the pump must overcome to move the water. Note:The above equation assumes the use of tubing thatis in the general range diameter as would be found in typi-cal homebrewing setups (see below for more on howdiameter effects flow rate). It will be fairly accurate fortubing from about 3⁄8 inches to 3⁄4 inches in diameter.Another assumption is that the tubing is smooth on theinside and not convoluted or corrugated.

3: COOLING RESERVOIRTo operate your chiller, get your bucket or cooler of chillerwater ready. A bucket will work fine, but a cooler will helpthe water stay cold a bit longer as well as allow you to chillthe water ahead of time and keep it cool until you’re readyto use it. For ice, you could just use a couple of bags of ice from

a local store, but that’s not the DIY spirit (and it costsmore). As an alternative, you can fill about a dozen alu-minum soda or beer cans and freeze them. I picked up thisgreat trick from the Covert Hops Society brew club basedin Atlanta, Georgia. You can also add salt to the ice waterin the reservoir to drop the temperature a few moredegrees. Why this works is outside the scope of this arti-cle, but Googling the term “freezing point depression” willgive a good explanation.


4: READY THE PUMP Attach some tubing to the pump’s outlet, which mayrequire a fitting. I used a 1⁄2-inch female NPT to 1⁄2-inch hosebarb fitting to make attaching the tubing easier. It is unnec-essary to attach anything to the pump’s inlet connection,and doing so will add to the system head pressure. Lowerthe pump into the reservoir, but don’t connect it to theimmersion chiller (see photo at left).

5: DROP IN THE IMMERSION CHILLER With 15 minutes or so remaining in the boil, put the immer-sion chiller in your kettle. This sanitizes the chiller and killsany bad things that might have piggybacked on the outsideof the coils.Now you can either start the chilling as normal with

groundwater and then switch to the chilling reservoir, oryou can start off with a very large volume of ice in thereservoir and chill exclusively with the recirculated water.Rather than use groundwater to do the initial phase of

the chilling, which can use a lot of water, you can opt toincrease the amount of ice in the reservoir significantly andchill the whole batch (down to about 70 °F/21 °C) withjust recirculated water. This method can save a tremen-dous amount of water (more than the previous method),but requires more preparation and equipment to performmost efficiently.

6: MAXIMIZE EFFICIENCYFor chilling five gallons (19 L) of boiling wort with thismethod, you’ll need approximately 44 pounds (20 kg) ofice. This is about five gallons (19 L) of frozen water, so ifyou freeze five 1-gallon Ziplock bags or about six 3-literplastic soda bottles filled with water, you’ve got 44 poundsof ice. (If you’re interested in how these numbers work, tryGoogling “latent heat of fusion.”)For maximum chilling efficiency, the water returning to

the reservoir from the chilling coil needs to be evenly dis-tributed over the mass of ice. Do this by attaching the out-let tubing to a sparging arm commonly used in continuous(fly) sparging setups (to build a sparge arm, see page 10 ofthis issue).

recirculating wort chiller

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