Jump to content
  • Welcome to the eG Forums, a service of the eGullet Society for Culinary Arts & Letters. The Society is a 501(c)3 not-for-profit organization dedicated to the advancement of the culinary arts. These advertising-free forums are provided free of charge through donations from Society members. Anyone may read the forums, but to post you must create a free account.

Using a Büchner Funnel


Chris Amirault
 Share

Recommended Posts

As I mentioned in the All about Bitters topic, I purchased this pump, Büchner funnel, filter paper and beaker set-up, and thought some others out there might find some detailed photos and notes to be useful. I've never used one before, so feel free to chime in with advice, corrections, and the like.

First off, the equipment. Here's the pump and filter papers:

gallery_19804_437_16836.jpg

The flask -- which for my purposes will be plenty big:

gallery_19804_437_77454.jpg

Funnel from the side:

gallery_19804_437_29133.jpg

Perforated funnel base:

gallery_19804_437_38438.jpg

More later tonight when I take a crack at filtering a few different things at home.

Chris Amirault

eG Ethics Signatory

Sir Luscious got gator belts and patty melts

Link to comment
Share on other sites

Maybe you already know this:

Wet the filter paper after you pull vacuum but before you put in your bitters. This will prevent undesirables from going under the paper before it is sucked flat. I've never used a little pump like that before. Will you have to continously pump it the whole time you filter?

Link to comment
Share on other sites

Thanks. That's one of the things I had assumed based on similar tips with other filters (coffee, stock), and it made a big difference. You don't have to pump continuously, as the pressure is only reduced a little by the liquid trickling down; about 10-15 pumps at the start, then 5-10 as needed, seemed to do the trick.

Here's the set-up ready to go.

gallery_19804_437_71656.jpg

I wasn't careful enough with the ceramic funnel and chipped a tiny sliver of glass off the beaker as I was preparing to wedge the funnel and stopper into the beaker. No crack, though, so it didn't have any effect on the function.

Here are the liquids I was filtering in their "before" state; even though i had poured off a lot, you'll see sediment and louche throughout. First, pineapple-infused rum:

gallery_19804_437_497031.jpg

Pineapple-infused Campari (for Toby Maloney's Riviera):

gallery_19804_437_60563.jpg

Hess house bitters:

gallery_19804_437_22034.jpg

John Deragon's grapefruit bitters:

gallery_19804_437_4294.jpg

Pimento dram:

gallery_19804_437_3776.jpg

Here's the funnel filled with pimento dram being filtered for the first time:

gallery_19804_437_9034.jpg

I started pumping away, getting a good strong flow, and as it slowed, I pumped harder and harder. Mistake. Here's the source of the great sucking sound you've heard so much about:

gallery_19804_437_3827.jpg

Basically, for the first filtering, it pays to take a bit of extra time. If you're in a hurry, it's easy to put too much pressure on the filter paper. I also learned that carefully pouring liquid off the top (instead of shaking it, say), letting that liquid filter first, and pouring in the louche and sediment at the end was a good idea; otherwise, that stuff sinks to the base of the funnel and impedes the action of the filter.

As you progress, the papers are, of course, covered with less and less sediment, which is a good indicator of how you're doing. Here's the pimento dram's penultimate filter:

gallery_19804_437_130203.jpg

There were big differences in the final filterings for each liquid. I focused on the pineapple-infused rum, as it was easier to see the results. Here it is after two filterings:

gallery_19804_437_374008.jpg

Pineapple-infused rum after four filterings:

gallery_19804_437_129405.jpg

The Hess house after four filterings was also very clear:

gallery_19804_437_47233.jpg

I didn't bother doing four filters for everything here, but that seemed to be the magic number. I've got a new batch of a Hess house bitters variation steeping, so I'll try to document that at each stage. The effects are quite drastic, as you can tell.

As for tips, it definitely pays to be patient and to resist the desire to increase the vacuum strength. Wetting the filter and pumping it a bit before adding the liquid you're filtering works well, too: you'll hear hissing noises that mean that there's a slight fold in the filter through which air is passing -- and thus through which the liquid could pass. Placing the filter directly in the center of the funnel and leveling the funnel are both good ideas, I found.

Chris Amirault

eG Ethics Signatory

Sir Luscious got gator belts and patty melts

Link to comment
Share on other sites

Boy, that equipment sure takes me back to my chemistry days. Do you feel that you are only removing visual haze and sediment, or are you also removing flavor? I would be interested to know just how many flavor compounds are in the sediment that is being removed.

Regards,

Michael Lloyd

Mill Creek, Washington USA

Link to comment
Share on other sites

I can't quantify how much flavor I'm removing by filtering, but I don't think it's much. Certainly the bitters and pimento dram aren't suffering from lack of flavor, and the pineapple-infused liquors are both still wonderful.

As for the stuff filtered out, my guess is it's not going to have much flavor left, especially the fruits. I tried a few strawberries after infusing some tequila with them and straining out the hooch, and they were devoid of any strawberry flavor; the pineapple was better, but I think it's because some of the chunks had been pretty large.

Next time, it would be interesting to scrape up some of the filtering residue, rinse it off (no fair tasting the liquor left on it), and see what's what. I think stuff with volatile oils may still have some flavor left, unlike the fleshy, giving fruit.

Edited by chrisamirault (log)

Chris Amirault

eG Ethics Signatory

Sir Luscious got gator belts and patty melts

Link to comment
Share on other sites

  • 2 weeks later...

"Crash out" = come out of solution as a precipitate.

This might potentially happen to some of the dissolved substances as the proof is drastically reduced where the solution contacts the water-soaked filter paper.

--

Link to comment
Share on other sites

Got it. That makes sense.

I've done the first filtering series for a batch of bitters here, and still am grappling with having a weak spot give in the filter paper. It's pretty clear now and settling out a bit more louche. I'm going to try to do the last run in the next few days, will grab the camera when I do.

ETA: I did the scrape test and there's not much there. It's not without flavor, and the louche is sweet, but it's mainly just sort of muddy.

Edited by chrisamirault (log)

Chris Amirault

eG Ethics Signatory

Sir Luscious got gator belts and patty melts

Link to comment
Share on other sites

Update. I've filtered both a batch of house bitters and a makeshift batch of mole bitters to good effect. However, last night, my wife was cleaning up and tried to remove the hose from the side arm at the top of the flask where the hose connects. It sticks very tightly, and, well, Andrea broke it off. I'm going to order a new one but, yeesh, that damned flask is pretty frail.

ET add the proper "side arm" name.

Edited by chrisamirault (log)

Chris Amirault

eG Ethics Signatory

Sir Luscious got gator belts and patty melts

Link to comment
Share on other sites

  • 3 weeks later...

Another update. I have a batch of jerk bitters steeping, and I took advantage of some ripe pineapples to infuse some rum in the fruit. When those are ready I'll filter them and take notes. Meanwhile, I noticed that the house bitters I've been building based on Robert Hess's formula got cloudy, and as Avery (BittermensAG) suggested no amount of filtering cleared them up. I'm letting them settle in hopes of pouring off the top. However, if anyone has suggestions for something I can do with this gadget to address the problem, I'm all ears.

Chris Amirault

eG Ethics Signatory

Sir Luscious got gator belts and patty melts

Link to comment
Share on other sites

  • 5 months later...

With the pineapple rum, are you just chopping the pineapple? Could you also puree it since you're going to filter it? You would get maximum extraction, though you would also end up with a lot of the juice and the attendant sweetness, which could be good or bad.

Wouldn't this also be good for making a bisque, where you take shrimp (crawfish, or lobster) shells, blend them, boil and then put them through the funnel? Basically, any application where you would otherwise use cheesecloth and press? Or is this just as time consuming?

Link to comment
Share on other sites

It's a matter of preference. If you puree the fruit you get a watery product, I think, so I go with chunks that can then be used for other applications (pineapple upside-down cake, e.g.) since it's retained more juice.

Chris Amirault

eG Ethics Signatory

Sir Luscious got gator belts and patty melts

Link to comment
Share on other sites

  • 5 years later...

Resurrection time:

 

Do you find that it drips quite slowly? I just got my setup and tested it out tonight. After a few minutes it's drop by drop. To do about 300ml took well over half an hour, but then my stuff had a LOT of gunk in it....

Link to comment
Share on other sites

If you have a lot of gunk, is there any way you can pre-filter to get at least some of it out?

 

Back in my synthetic organic chemist days, it was pretty rare for us to filter through a Buchner funnel with a paper. When we were working up reactions, a very common last step before purification was to add a powdered drying agent and swirl it around. It would suck up any last bits of water or aqueous solutions. Then to get rid of the drying agent, we'd send the whole thing through a fritted funnel topped with a layer of Celite (diatomaceous earth). The Celite wouldn't clog as quickly as a filter paper would, and if it did it was easy to scrape off the top bit with a metal spatula and clear out the filter bed. (Side note: home beer brewers live in dread of a stuck mash: when the grain bed clogs up and the water can't flow through. The classic homebrew solution is to add some rice hulls to the mash grain. The rice hulls act sort of like the Celite, sort of like a pre-filtration, to catch the fine stuff that can gum up the rest of the works.) Anyhow, when we'd dried and filtered the solution, we'd pop it on the rotovap to remove the solvent, sometimes pump on it with a vacuum to make sure all the solvent was gone, and then purify our compound by some appropriate means.

  • Like 1

MelissaH

Oswego, NY

Chemist, writer, hired gun

Say this five times fast: "A big blue bucket of blue blueberries."

foodblog1 | kitchen reno | foodblog2

Link to comment
Share on other sites

Well, a fine mesh strainer doesn't help, and a coffee filter hardly works. I figure as far as relatively budget friendly option goes, it was that or gelatin.

 

 

ETA: I should have mentioned I was a filtering a liqueur, so maybe the sugar had something to do with it.

Edited by Hassouni (log)
Link to comment
Share on other sites

There are different grades of filter paper with different porosities.  The clogging of Whatman#1 with fine particulates is a common phenomenon in the lab, heh.  How about a sintered glass funnel (I'd go w/ M porosity) plus a bed of celite, prewetted and tamped down with a spatula or (preferably) a glass rod made so that it has a flattened end? Highly aqueous solutions would tend to mess up the celite, though, so high-proof (high alcohol) stuff would work better.  (Of course, in this case the use of anhy. MgSO4 or Na2SO4 etc would not be advisable because these would be aqueous solutions... :-) )

Edited by huiray (log)
Link to comment
Share on other sites

Well, a fine mesh strainer doesn't help, and a coffee filter hardly works. I figure as far as relatively budget friendly option goes, it was that or gelatin.

 

 

ETA: I should have mentioned I was a filtering a liqueur, so maybe the sugar had something to do with it.

Its on a vacuum flask, right?

Link to comment
Share on other sites

Hassouni, have you tried lining the fine mess strainer with a few layers of dampened cheesecloth as an initial filter?

I have not...

 

Its on a vacuum flask, right?

Indeed, with most of the air sucked out

Link to comment
Share on other sites

 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...