I succeeded in vacuum-sealing the Vitamix Ascent lids with an easier setup than my original DIY Vitamix vacuum lid. For information about why you might want to vacuum blend, see my vacuum blending post.
When I first saw the Ascent containers, I was excited that their new lids would make them easier to vacuum seal than the classic Vitamix containers. The Ascent lids are rigid with a gasket, and they snap on securely. The stock lid plug is vented, but my idea was to replace it with a piece of acrylic and a flat gasket that would seal onto the top of the lid.
This setup would be much easier to make than my first Vitamix vacuum lid, because the dimensions of the acrylic don’t matter, as long as it is bigger than the opening. Also, since the top gasket doesn’t have to slide into place, it doesn’t need to be oiled.
However, I found that the stock gaskets don’t seal as well as I had hoped. The 64-oz Ascent lid holds a partial vacuum, but starts leaking around 16 inHg (about half of full vacuum). That’s enough to see some benefit from vacuum blending, but a better vacuum would be preferable. Worse, the 48-oz Ascent lid doesn’t hold any vacuum. This was disappointing, but I had an idea to fix it without too much extra work.
I decided to try adding a gasket (in the same place as the stock gasket) to make a tighter seal. I put o-rings both on top of the stock gasket, and in place of the stock gasket. The stock gasket has a T-shaped cross-section: My guess is that the Vitamix designers chose this shape to minimize the amount of food that gets under it, so that you don’t need to take it off for cleaning every time you use it. (I do wonder why they didn’t choose a gasket that would seal better, especially for the 48-oz container.)
I first tested a variety of o-ring gaskets without oiling them. With no oil, none of the o-rings formed a good seal when used on top of the stock gasket. When I removed the stock gasket, I found that 3/16” (nominal) thick o-rings do form a vacuum seal on both the 48-oz and 64-oz containers.
When I oiled them, I found that the 1/8” (nominal) o-rings will form a seal when used on top of the stock o-ring. (This setup has the advantage that food is less likely to get under the gaskets, making them easier to keep clean.)
Even though they don’t need it, it will probably extend the life of the 3/16” o-rings to oil them. Because the o-ring is slightly protected by the rest of the lid, it’s less annoying to keep it oiled than it was for my original DIY design.
The setup you prefer will probably depend on how much your blends splash up inside the lid. With lots of splashing, I think the 1/8” o-rings are preferable. On the other hand, you might find that you prefer to not have to oil the o-ring. The o-rings are cheap enough that you might as well get a few different ones and see which one you prefer.
These o-rings make it slightly harder to pop the lid on and off, but I didn’t find it a problem. (I can put on and take off the stock lids with one hand, but it usually takes two hands for the o-ring lids.)
I ordered o-rings from The O-Ring Store. They have FDA-compliant food-grade silicone o-rings. Here are sizes that worked:
Over stock gasket: AS568-252 (5 1/4” ID x 1/8” CS nominal)
In place of stock gasket: AS568-355 (5 1/4” ID x 3/16” nominal)
Over stock gasket: AS568-256 (5 3/4” ID x 1/8” CS nominal)
In place of stock gasket: AS568-360 (5 7/8” ID x 3/16” nominal)
They also sell FDA-compliant N-Buna (nitrile) o-rings in these sizes. I’m not sure which type will hold up better in the long term, but so far the silicone ones are doing fine.
I recommend cutting the top gasket from this silicone sheet. It is thicker than the other inexpensive silicone sheets that I’ve seen, so I think it will hold up better. I used an X-Acto blade, but you can also cut it with scissors.
I also tried to make a flat gasket by pressing a ring of silicone caulk from a tube between two pieces of acrylic covered with wax paper and using pennies as spacers. However, this caulk-based gasket did not work well, so stick with the sheet one.
I used a circle of 1/4″ thick cast acrylic to seal over the top gasket. If there’s a TAP Plastics or similar store near you, they likely have a scrap bin, and you can pick up a piece for cheap (or free). The nice thing about this design is that the dimensions of the top piece don’t matter, as long as it is at least as big as the flat part of the Vitamix lid. I cut it with a community laser cutter, but if you don’t have access to one, there are other ways of cutting it (score and break, or with a saw). It needs a small hole in the middle, and I laser-cut a 0.17″ hole.
I improved on my first DIY vacuum blending setup by incorporating a one-way valve on the container. All commercial vacuum blenders use one, and it turns out it’s pretty simple to make. The main advantage is that ingredients can’t splash up into the tube to the vacuum pump during blending. If that happens, it’s a pain clean out. You need to make sure the line is clean and dry before running the pump, because if the pump sucks in any liquid, it will likely be ruined. All you need is a flat piece of silicone to cover the small hole in the lid. You can either cut a piece from a silicone sheet or you can squeeze out a dime-sized circle from a silicone tube onto wax paper. I attached a little L-shaped piece to hold it in place. I’ve also seen people use a small flap of electrical tape to make an easy one-way valve.
To use these one-way valves I drilled a hole in a rubber sink stopper and sealed it onto a piece of tubing: (Thanks to reader Jay for the stopper idea.)
I also built a little box for my vacuum pumps out of acrylic scraps. It is tidier than my original cardboard box, and it has a power switch, so now I don’t have to plug and unplug them every use. The pumps had a strange behavior when activating them by plugging them in: sometimes they wouldn’t start properly. The power switch makes them work every time.
(The aluminum foil is there because I wasn’t sure if the brass fittings were food-safe, so I didn’t want to be touching them while handling food.)
If you don’t want to rig up your own pump like this, you could use a vacuum sealer with accessory port. I may test some other pumps in the future.