I think Vitamix blenders are the best on the market, so when I decided to investigate vacuum blending, I rigged up a Vitamix vacuum blender container. The first thing you need for a vacuum blender is an air-tight container. Unfortunately the classic Vitamix lids do not form an air-tight seal. Initially I thought I could just seal the hole in the middle of the lid, but it turns out that the edge of the lid that seals against the container does not hold up to vacuum.
If you decide to make your own, keep in mind that doing so voids the warranty. I haven’t had any problems with my modifications, but proceed at your own risk.
Interestingly, the new Ascent Series Vitamix lids have an airtight gasket, but I wanted to be able to blend smaller amounts for my testing. Vitamix has plans to release a smaller Ascent container, but I don’t know when it will come out. I decided to make a sealed lid for a 32-oz classic Vitamix container.
The first challenge with sealing a Vitamix container is that the top is not flat, so you can’t just use a flat gasket. However, we are fortunate on a separate matter: directly below the pour spout the inside of the container is a perfect circle. So I decided to make a lid to seal against that circle. Below that circle, the walls transition to a square, so that transition point prevents the lid from going too far into the container.
Here’s the overview: I cut a piece of acrylic for the lid, and then I cut a slit in silicone tubing and put it around the acrylic to form a gasket.
I used a laser cutter to cut the acrylic. You might be surprised to find a laser cutter that you can use near you. Search for fab lab, makerspace, or hackerspace. I’ve also heard that some libraries have them. You could also use a saw.
Parts list for lid
(Note that Amazon prices jump around, so some of these might no longer be the best deal. Also, these are affiliate links, so I get a little commission if you order via them, at no extra cost to you.)
Total cost is about $100 to $170, depending on how many of the tools you already have, and if you opt for the optional vacuum gauge and valves.
1/4″ clear acrylic sheet (if there’s a TAP plastics or similar store near you, you can save money by buying a scrap piece from them. Or, if you find a place with a laser cutter, they may have scraps for free.)
1/4″ID, 1/2″OD Silicone Tubing (for gasket)
1/4″ ID vinyl tubing (for vacuum lines)
Tools you’ll need:
7″ hose clamp (cheaper at local hardware store or home depot)
Making the lid
For the 32-oz Vitamix container I cut a 4.9″ disk from the acrylic, with a 7/16″ hole for the tap. Then I rounded the top and bottom of the outer edge of the disk with the file. I filed it so that the corners have about a 1/16″ radius, evenly all around the disk.
I cut a piece of the silicone tubing to go around the disk, and cut a single slit along its length. Getting just the right length is tricky, so I used the first piece as a rough draft, and then adjusted the length to get the second piece just right. You can also check that the lid with silicone around it will go onto the container. It has to slide in a bit, so I rubbed it with a little cooking oil, to allow it to slide in. If it’s too tight, you can file off a bit more of the acrylic.
When you cut the silicone you want the cut to be straight and perpendicular to the tubing length. I found it hard to get a nice cut when trimming off small amounts, so that’s why I used the “rough draft” piece for sizing help. The silicone is flexible enough that there is a bit of leeway.
Try to keep the silicone tubing clean.
I put the correct length piece of slit silicone tubing around the disk. I used masking tape to tape one end in place and applied silicone sealant to the flat end of the tubing. Then I put the other end of the tubing flush against the first end, and taped it in place as well. I also put a piece of masking tape over the joining area. Then I used a hose clamp to hold everything in place while the silicone cured. The hose clamp goes around the outside of the silicone tubing on the disk. The hose clamp does not have to be tightened super-tight, just enough to keep the ends flush. I put masking tape on the inside of the hose clamp that would contact the sealant. I let it cure for 24 hours, and then removed the hose clamp.
Then I cut threads in the middle of the lid for the barb fitting using the tap and crescent wrench. I wrapped the fitting in PTFE tape, and screwed it in.
I also ended up sealing the interface between the slit silicone tubing and the disk with silicone because sometimes blending liquid splashed up, and it was able to get between the lid and the inside of the silicone tubing gasket.
There are manual vacuum pumps, but I figured it would be more convenient to have an electric one. The first ones I found are the big ones with a handle that people use for HVAC work. However, I think those are overkill for this application, and I also learned that they exhaust a fine mist of oil particles. That’s fine if you’re in a work site or garage, but I figured it would be too messy for the kitchen.
Then I came across these small 12V electric vacuum pumps on Amazon. I decided to get two to try running them in series. I got the cheapest, and the second cheapest, and they appear to be identical aside from the label. According to my vacuum gauge, each one pulls 21 in Hg, and together they pull 27 in Hg. The lid is able to hold that vacuum without leaking for the minute or two it takes to blend. (I didn’t do long term leak tests because they’re not relevant to vacuum blending.)
I haven’t done comparative testing to see how much extra benefit the second pump gets you. It’s the difference between removing 70% of the air and removing 90% of the air. I figured if I’m taking the time to do this, it’s worth going for the double pump setup.
If you use those 12V vacuum pumps you’ll need a 12V power supply. I was able to find an old one around the house, but if you don’t have one, you can get one on Amazon. I measured the 12V vacuum pumps use 650mA at vacuum. (The cheaper of the pumps, which is the one I recommend, has some false information in its description stating that it uses up to 96W—that is just wrong.) I’d round up and use a minimum of 1A per pump, maybe 1.5A to be on the safe side. I’m running the two pumps on a 3A power supply.
If you go this route, you’ll also need a plug, wire, solder, and soldering iron to connect it up. If you found a place with a laser cutter, they may also have these materials available.
Alternatively, you could get a pre-wired pump for a vacuum sealer like this one (or if you already have a vacuum sealer, some of them have an accessory hose). You could also try a hand-powered pump; here are instructions for converting a bike pump.
A vacuum gauge is optional, but I think it’s nice to have, since you can use it to check that you don’t have leaks, and also to tell what kind of vacuum you’re pulling. You also don’t necessarily need valves, but I decided to get them to make it easier to remove the lid. If you don’t get valves, you’ll remove the vinyl tubing from the barb on the lid each time you open it.
There are various configurations that would require other fittings, but I think the one I have with the cross, valves, and gauge at the pump end of the tube works pretty well.