In many ways, a homebrewery is simpler than a commercial brewery. One aspect of homebrewing that is typically much simpler is the transfer of wort and beer around the brewery. In a commercial brewery, the vessels — the hot liquor tanks, mash and lauter vessels, kettles, whirlpools, fermenters and bright beer tanks — do not move and in most the wort or beer is pumped between them. (In a few, tanks are on different levels, allowing for transfers via gravity.)
In a small brewery, the pumps may be mobile and connected to the appropriate tank via temporary hoses as needed. In a larger brewery, all the piping may be fixed, with a dedicated pump for every transfer. Commercial brewers need to worry about fluid transfer rates, cleaning fixed piping in place and the potential for overpressure (or underpressure) situations in the piping.
Although we homebrewers (thankfully) have things a little easier in this respect, there are a few things every homebrewer should know about transferring wort and beer. Transferring liquids in a homebrewery should be relatively quick and the transfer should occur without contamination or unwanted aeration.
Transfers by GravityIn most homebreweries, most transfers occur via gravity. In a 5-gallon (19-L) scale, vessels to be drained of wort or beer often sit above the receiving vessel in the brewing setup. In a vertical 3-tier system, the vessels fit into a frame. For a kitchen brewer, the hot liquor tank may sit on top of the fridge, the picnic cooler mash/lauter tun on the counter and the kettle on the floor during wort collection. In cases where the holding vessel is not “permanently” stationed above the receiving vessel, it can be easily picked up and elevated prior to the transfer.
SpigotThe easiest type a transfer to perform occurs when a vessel has a spigot attached — just open the valve and let the liquid flow. The liquid is usually channeled by clear plastic tubing (such as Tygon tubing) into the receiving vessel. If you are contemplating buying any piece of equipment for your brewery and you have the option of adding a spigot (for example, a ball valve on a kettle), consider it carefully — although it costs more initially, it will save you a lot of time and energy in the long run.
During most transfers, except for the transfer of cold wort to the fermenter, avoiding aeration is a priority. The simplest way to do this is to place the outflow end of the tubing at the bottom of the receiving vessel. Don’t let the liquid fall through the air and splash into the receiving vessel or fan down the side the vessel. Keep the tube at the bottom of the vessel and — once the bottom is covered with liquid — keep the end of the tube under the liquid level. When I transfer, I tilt the receiving vessel slightly and place the end of the tubing at the lowest point. This way, the end of the tube gets covered by liquid more quickly (perhaps reducing aeration very slightly).
SiphonIf your holding vessel doesn’t have a spigot — for example, when transferring from a glass carboy — you will need to start a siphon. Homebrewers usually siphon with a racking cane with clear tubing attached. There are three popular ways to start a siphon — by mouth, by filling the racking tube with water or by using a siphon starter device.
Starting a siphon by mouth is simple. Just place the racking cane in the holding vessel, place the outflow end below the vessel and suck on the tube until the liquid starts flowing. Although simple, many brewers eschew this method out of fears for contamination. (Some gargle with vodka before putting their mouth on the tubing, although this likely does little to reduce the levels of bacteria in their mouth.) In practice, starting a siphon by mouth doesn’t lead to routinely contaminated beer. However, there are easy methods of starting a siphon that remove this potential source of contamination.
One sure-fire way to start a siphon is to completely fill your racking cane with water. Hold the cane so both ends are at the same level (to keep the water from draining out). Then, in one coordinated movement, lower both ends of the tube. While lowering, the “cane” end of the racking cane goes into the holding vessel and the tubing is lowered into the receiving vessel (which is, of course, positioned below the holding vessel).
Keep the ends of the tubing at the same level until the cane end is submerged in liquid, then quickly drop the tubing into the receiving vessel. This will prevent water from flowing from the cane into your beer or wort.
You may want to run the first bit of water into a pitcher before directing the stream of beer to the receiving vessel. To do this, let the pitcher fill until the water is displaced from the tubing, then pinch the tubing and move it to the receiving vessel.
There are a couple types of siphon starters that provide another easy way to get liquid flowing. One design is basically a tube within a tube. The device is placed in the holding vessel as a racking cane would be. The brewer then pumps the siphon starter and the liquid starts flowing. The remainder of the transfer occurs via gravity (i.e. you don’t have to keep pumping the whole time). Another design involves a marble in a little metal “cage” at one end of the tubing. The marble end is placed in the holding vessel and moved up and down rapidly. When the tube moves down, liquid is forced in to it. When the tube is lifted up, fluid pressure on the marble closes the opening. By rapidly moving the tubing for several seconds, liquid begins filling the tube. Once enough liquid is in the tube, a siphon is started.
Most homebrew shops carry one or both of these siphon starters. The advantage of these devices is that it takes less coordination to start a siphon compared to the filled racking cane maneuver. The disadvantage is that they are a little bit harder to clean.
Pumping wort or beerSome homebrewers use pumps to move their wort and beer (as well as circulate it in RIMs and HERMS loops). The advantage of using a pump is that liquid can be moved uphill or between vessels at the same level. In addition, most popular homebrew pumps move the liquid faster than it can be drained by gravity. The only real disadvantage is their initial cost. For 5-gallon (19-L) stovetop brewers, a pump is a luxury. For homebrewers making larger volumes of beer, they are handy and for brewers who have horizontal 3-vessel brewing rigs, they are indispensible. (See the November 2003 issue of BYO for more on pump types and selecting a pump for use in a homebrewery.)
The most popular kind of pump for homebrewers is a centrifugal pump. One of the most popular is a model manufactured by March that sells for around $130 (US). Their pump is food grade and rated for temperatures up to 250 °F (121 °C), so it can transfer or circulate hot wort. It also has a magnetic coupler, so if bits of grain get lodged in the impeller, the shaft won’t break. (The impeller is the spinning part that “throws” liquid out of the pump.)
These pumps work great, but two common problems do surface from time to time. Centrifugal pumps are not self-priming and the pump will quit moving liquid if there is a large enough bubble in the stream of liquid. Situating your pump at or near the lowest point in the tubing goes a long way towards avoiding this problem. If a bubble forms (or is sucked into the line), it will rise in the liquid up past the pump and the pump will again be primed. Keeping all your fittings tight will likewise help keep air from being drawn into the pump as it works.
The second potential problem is cavitation. It does not happen often in homebrew situations, but it can pit the inside of your pump if it does. Cavitation occurs when low pressure inside the pump causes a “bubble” of liquid vapor to form. The “bubble” collapses and makes a loud sound. (Did you know that audible cavitation occurs in the xylem of trees? It does. Did you know that the Navy is developing high-speed torpedoes that travel inside cavitation bubbles, reducing friction because the torpedo never touches water? They are. Did you know that, during cavitation, the collapsing “bubbles” release photons (i.e. emit light)? They do. Did you know that a Google search for “cavitation” brings up all sorts of factoids that have no relevance to homebrewing? It does!)
If you’re recirculating hot wort through a mash and slow flow through the grain bed is making the pressure between the grain bed and pump drop, you might experience cavitation. The usual cures for cavitation are to lower the temperature of the liquid being pumped, raise the pressure on the input side or slow the speed that liquid is being pumping. When brewing, the first two are not options, so slowing the pump is what you need to do. One way to slow the pump is to restrict the output. Most centrifugal pumps sold for homebrewing use can withstand a little back pressure, but check your owners manual to make certain before you try it with your pump. To restrict the output of your pump, just use a tubing clamp on the outflow tubing.
Pressure transfersCornelius (“Corny”) kegs are a popular method for storing and serving beer. However, they can also be used as fermenters with the proper fittings attached. An advantage of using a Corny keg as a fermenter is that beer can be transferred between Corny kegs via CO2 pressure with no exposure to oxygen during the transfer.
Let’s say you have a full Corny keg you’ve used as a secondary fermenter or lagering tank. Clean and sanitize a receiving keg and fill it with water. Connect your CO2 tank to the receiving keg and push all the water out through a tap. Now you have an empty keg filled with CO2. It’s best keep the keg weakly pressurized, around 3–5 PSI.
Next, connect your CO2 tank to the Corny with beer in it, keeping the pressure the same as in the receiving keg. Make a “jumper” line by attaching two “beer out” fittings to a length of tubing. (These are usually black on ball lock/Pepsi kegs.) Attach the jumper line to the “beer out” posts on both kegs (the posts that connect to the spear that extends to the bottom of the keg). To transfer the beer, release the pressure from the receiving keg. The simplest way to do this is to attach a “gas in” fitting (usually grey for Pepsi kegs) to the “gas in” post and let the keg vent. (This is why you want only a small amount of pressure on the keg.) Beer will move up the spear and out of the first keg and down the spear and into the second keg. Remove the connectors once the keg is full and there you have it— a transfer in which the beer is not exposed to oxygen. (OK, a tiny amount will diffuse into the receiving keg against the flow of CO2 out the keg, but not much.)
If you are transferring beer from a secondary fermenter to your serving keg, the first little bit of beer transferred will be very yeasty. The pickup tube will suck in yeast sediment at the bottom of the secondary fermenter and transfer it to your serving keg. To eliminate this, just watch the tubing and disconnect the jumper line once the beer changes from cloudy to clear. Connect your CO2 tank and a cobra tap to the receiving tank and blow out the yeasty beer. Then reconnect your setup and transfer the clear beer.
If you attempt to transfer fully carbonated beer this way — perhaps from a 5-gallon (19 L) or larger Corny keg to a 3-gallon (11 L) keg — you may experience problems with foaming. As the beer that has been stored under serving pressures enters the receiving keg at low pressure, CO2 can break out of solution. The solution is to make the initial pressure in the receiving keg equal to the pressure the holding keg has been kept at. Then, release the pressure very slowly so the receiving keg is only a few PSI lower than the holding keg. (You won’t know what the pressure is unless you have a gauge on the receiving tank, but you can judge the relative pressures by how fast beer is flowing through the jumper tubes.)
The best way to do this is to attach some tubing to the “in” fitting that is serving as a vent. Either clamp the tubing in such a way that the pressure is released slowly or keep the tubing clamped shut and periodically let out little bursts of CO2. Watch the jumper tubing and let out another burst of CO2 when the beer flow stops. You can also do the stop and start method using the pressure release valve on the receiving keg, though this may cause excessive wear and tear. If you take care in transferring your wort and beer, the final beer transfer --from your glass to your mouth--should be very enjoyable.