DIY Vacuum Pump
Posted Feb 28th 2013 | By:
I bet if you ask on winemakingtalk, "What is the best wine makers gadget?" The resounding answer will definitely be... a vacuum pump. This inexpensive tool helps us in so many different aspects, from racking, to degassing, filtering, and even bottling. There are a few commercial vacuum units available that work very well but you can also make a DIY vacuum pump for a fraction of the cost.
This article will describe my DIY vacuum pump used for racking and degassing. I will outline the steps for building the pump and also post videos showing the process for using the pump properly.
This project involves electricity and negative pressure. Imploding carboys can be very bad for your health. Check your carboys for cracks before you put them under vacuum. A carboy could theoretically implode under any amount of vacuum even if there are no cracks. Do not move or contact the carboy with any foreign object while the carboy is under vacuum. I am not responsible for any damage or injury caused by the use of this information.
That being said, I have never heard of a catastrophic carboy failure. Do not try to use a vacuum pump with better bottles or other plastic carboys. They are not strong enough to hold the vacuum.
Much of this build was inspired by Wade E. Check his thread here
- 1 x Vacuum pump from All Electronics. $35.95CAD shipped to Canada. Thanks to SLOweather for the find. Link
- 1 x Brick style Power Supply - 12VDC 6A. $8.15CAD shipped to Canada. eBay
- 1 x Double Spout Carboy Cap from my local shop. $3.40CAD
- 1 x Vinyl Braided Reinforced Tubing 1/2 in. OD x 1/4 in. ID x 10 ft. $8.80CAD Link
- 2 x Curved Plastic Racking Cane from my local shop. $2.50CAD
- 1 x Standard Racking Hose to fit the canes from my local shop. $2.00CAD
- 1 x Ball valve with 1/4 in. barb. ~$5 from eBay.
- 4 x Hose Adapter 1/4 in. barb x Male NPT Nylon with nut. $3.50CAD From my local indoor gardening store.
- 1 x Jar from my wife.
Total damage = $82.30CAD
The pump I used was from an online surplus store. Last I checked there is no more stock. Something similar can be creating using a car tire pump, refrigerator compressor pump and even a vacuum food sealing unit. Probably the best choice would be to use a car tire pump. Those will typically give you around 23 inHg of vacuum which is perfect for our application. Here are some links.
Instructables tutorial on how to build a vacuum pump
Receiving Carboy Cap
I chose to use a carboy cap instead of a bung. Although the most of these style caps do not make a 100% air tight seal with the carboy lip, it does seal well enough and I find it quite convenient for my setup. I had to cut 1cm off the top of the main spout to allow the racking tube to slide through. It is an extremely tight fit. Push the racking tube far enough so it reaches to the bottom of the carboy to minimize splashing and oxidation unless ofcourse, you want to splash rack. Situations where you might want to splash rack are...
When your transfering from primary to secondary and you want to energize the yeast with a little oxygen.
When you are at the degassing stage as the extra agitation will help move the CO2.
The vacuum tube from the pump connects to the secondary spout on the carboy cap. I used the end of a standard BIC pen. The barrel fit the carboy cap perfectly air tight but still loose enough that I can remove it when required. The hose end even has a barb to keep the hose tight. Couldn't be more perfect!
Here you can see the finished receiving carboy cap assembly. The hose I chose is PVC with a vinyl braid reinforcement. It's probably overkill but I can guarantee that this hose will never collapse at the pressure that the pump can generate. It's also a little unwieldy, I would have liked something a little more flexible but the selection at Home Depot was limited. The material is PVC so it isn't food safe, but this section of hose will hopefully never touch wine so I'm ok with that.
An overflow tank is required to protect our pump from sucking up any liquid. If the receiving carboy fills to the top and starts to draw up wine, it will first empty into the overflow tank which gives you an extra buffer to realize your screw up and shut the pump off. I never intend on running the pump unattended so I only chose a small jar as my overflow tank. I suggest you use a larger jar if you are easily distracted or the forgetful type. The overflow tank is really just an airtight vessel with hose barbs for input, output and any extras you may wish to add. You can make it with whatever materials you have on hand. Probably the nicest solution would be a Buchner flask if you happen to know a chemist.
Start by drilling holes in the lid for the hose barbs. I chose to make four holes. One for input, one for output, one for a bypass valve and one for a gauge. The gauge is not required for a working vacuum pump, but it does allow you to make fine adjustments to the amount of vacuum. Bare minimum is three holes.
Apply some silicon sealant on the flange of the hose barb. I just used regular bathtub sealant because that's what I had lying around. Depending on the materials that you acquired, you may need to do things a little different. You may need to add washers, etc to make it all air tight.
Apply more sealant to the inside threads and tighten down the nut. Nylon parts can't be tightened too much so don't put too much muscle into it. Clean up the excess sealant with a damp finger.
Repeat for all hose barbs.
This is your finished overflow tank lid. Make sure the inside nuts do not interfere with the jar when you close the lid. Let the lid sit overnight before applying vacuum so the sealant can set.
The Bypass Valve
The bypass valve allows you to remove vacuum instantly. The issue is that when you turn the power off, there is still vacuum present in the system so the pump does not stop moving fluid when the switch is flipped. With a valve, you can dump the vacuum and stop the pump instantly. I had this valve in my junk box. If you search eBay for "ball valve" you will find many examples to choose from. Just choose something with an appropriate hose barb and you're good to go.
The Gauge (optional)
A gauge is probably not required for most cases. I got one for cheap from eBay so I added it to the build. Look for something that goes from 0-25 inHg. I had to MacGyver something up to adapt from the gauge port to the overflow tank barb. Use what ever you can find. I had to use a short piece of racking tube and the remains of the pen from the carboy cap assembly.
The Power Supply
The pump needs 12 volts DC at about 2A when it is peaked out (pulling max vacuum). I'm using a 12VDC 6A laptop power brick from eBay for $10 that works perfectly. I wired it through a common light switch to provide an easy way to turn the pump on/off. Connect the negative lead from the power brick to the negative lead of the pump. Connect the positive lead of the power brick to one terminal of the light switch. The other terminal connects to the positive lead of the pump. It is all low voltage so there shouldn't be any fire or shock hazard but still I must give you the standard warning, if you have no experience with electrical circuits, you must seek the assistance of an experienced electrician.
Put It All Together
This is the completed system mounted to a piece of scrap wood. Connect a short hose from the input port on the pump (output port is left empty) to one of the barbs on your overflow tank. Connect another overflow tank barb to the output hose which will connect to the carboy cap. Plug the bypass valve and gauge to the remaining ports.
Here is a video showing the process for racking from primary bucket to carboy. I had already racked prior to this video so there was no gross lees in the primary. If I was doing the first racking from primary to secondary, I would be a lot more careful not to disturb the lees.
The process for degassing is pretty simple. Remove the racking cane from the center of the carboy cap and replace with a cap. I typically remove enough wine so the level is down close to the shoulders of the carboy (not shown in the picture below). That way there is more surface area and more room for the bubbles to disperse. Turn the pump on and let the vacuum build to 23 inHg. You can turn the pump off once in a while to let it rest as it will hold the vacuum. Also, I find it degasses faster if you open the bypass valve once in a while and build the vacuum again. Keep the carboy under vacuum until the small bubbles stop and they start becoming large bubbles. Temperature is very important for quick degassing. I bring the carboy up to 25 degrees C and it usually finishes degassing in under 5 minutes. Different batches will vary, there are no hard rules for timing.
The vacuum pump is probably the most useful tool you can add to your wine making arsenal. For less that $100 worth of parts and a little elbow grease, you can put together a system that rivals the performance of the expensive retail units.
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