Faucet Aspirators

[Judy Wilson]

A while back, someone wrote in to ask us:

"The section of vacuum filtering for essences/consommes I'm very intrigued by, but being charged by the L of water I use, the faucet aspirator although inexpensive may overall end up costing more due to the amount of water I use. So I've been looking and there are kit's being sold with the Buchner funnel, flask and all of the vacuum hoses and other accoutrements but they attach to a hand-held pump.

Unfortunately it doesn't give an idea of the PSI it's able to achieve or anything really and I was just wondering if you had any experience using these."

Anyone have any recommendations?

[Anonymous Modernist 347]

I built a home-made vacuum pump, using a faucet aspirator and a pump of the type that is used in the southwest to circulate water through a "swamp cooler". The pump is partially submerged in a plastic tank, and the faucet aspirator drains back into it, so there isn't any water wastage. "The water goes round and around..."

This is used with an Erlenmeyer flask and a Buchner funnel. The faucet aspirator pulls a reasonable vacuum, although I've never measured it.

But when I tried to use it to filter some watermelon juice, the filter in the Buchner funnel clogged pretty quickly, and the yield was very slow. I haven't used it for anything since then, but I wasn't overwhelmingly impressed. Perhaps I should have used a coarser filter paper.

I recently tried making the oxtail consumme, and fining it with methylcellulose as discussed in 2-376. Surprisingly, after straining it, chilling it and scraping off the fat, I tried simmering it once more, and was quite surprised at the extent to which the methylcellulose bubbled up again, with more particles, so I strained it again, using a double layer of cheese cloth and a fine sieve.

It might be interesting to chill and then simmer it yet another time, and this time run the hot broth through the Buchner funnel, to try to get the ultimate clarity.

[Anonymous Modernist 393]

You can also look at either vacuum aspirator - which recirculate water, very similar to what robert described... you can also find dry and oil driven vacuum pumps... although dry and oil pumps tend to be more expensive. I would look on ebay for a vacuum aspirator. I bought one from a government auction website for $65 and it achieves an ultimate vacuum of 20 mbars out of each port (2 ports).