Latex-flavored coffee tastes horrible
February 5, 2008 3:04 PM   Subscribe

How do I avoid burning coffee with a stovetop espresso maker?

I have a Bialetti Moka Express, 6-cup espresso maker. I have had it about a year.

General advice is to replace the rubber seal and filter plate once a year. Which I did last week. I threw away the old seal and plate.

I made a batch of coffee, threw it away. I made another few batches, which tasted just fine.

Within the last week, every batch I make takes on a bitter, burned flavor. Distinctly unpleasant, with hints of rubber. I'm not changing my coffee or coffee-making process in any way.

Do I simply need to replace the seal again to fix this? What other possibilities are there before I spend more money?
posted by Blazecock Pileon to Food & Drink (14 answers total) 10 users marked this as a favorite
I find that boiling coffe too slowly causes it to burn, you need to boil the water very quickly. It is possible that your new seal is too good and your old brewing time was too slow. Try the fast method and see what happens.
posted by 0bvious at 3:07 PM on February 5, 2008

Best answer: I have one of these - same brand and everything. How long are you leaving it on the stove, by the way? I get the best results when I take it off the instant I can hear that the coffee is spilling up into the pot - before that famous sucking sound. The coffee will still fill the pot once it's off the , and you won't burn the stuff.

If you made a few successful batches and it's only doing it now, though, it could just be that you got a crappy seal. If you're doing everything right and the seal's not that old but you're still getting that nasty flavor, I'd replace the seal. If it's STILL happening, then it might be a good idea to give Bialetti a call.
posted by katillathehun at 3:12 PM on February 5, 2008

On the contrary, my experience with making the best espresso in the little stove-top units is to heat the water to boiling, then assemble the unit, (do NOT tamp down the coffee, that may be your trouble) and then replace the unit on the range, at high heat. Immediately when the espresso begins coming out, turn the heat WAY down, but it must be warm enough to maintain pressure. Remove the unit when the coffee starts to sputter out -- if possible, plunge the lower portion into cold water to arrest this -- the bad tasting coffee comes out last, with these units. Getting good espresso out of them is possible, but it takes a bit of skill.
posted by Rash at 3:14 PM on February 5, 2008

Ah, you're using the big model (the six-cup). I was never able to make decent espresso with those -- smaller is better with stove-top.
posted by Rash at 3:15 PM on February 5, 2008

Response by poster: I've got the stove on Hi -- the highest setting possible.

I leave the pot on the stovetop and let the pot boil through the "sucking" sound about 10-15 seconds, because if I turn off the heat, the water almost immediately stops boiling and stops percolating steam through the filter, or slows to a crawl. That 10-15 seconds seems to be necessary to boil a full pot.
posted by Blazecock Pileon at 3:17 PM on February 5, 2008

Response by poster: The 6-cup is actually quite small; it references six espresso-sized cups. I wouldn't know how to safely assemble the maker while the water is boiling.
posted by Blazecock Pileon at 3:19 PM on February 5, 2008

Hmm, never had this problem, let's see. At my house we turn the heat up all the way, and we turn the heat off immediately when the water starts to boil.
posted by salvia at 3:23 PM on February 5, 2008

All of the above advice is good. Here is a trick for times when the pot misbehaves despite all your best attempts, and goes sput-sput-sput instead of having the coffee come creaming out of its spout: fill a bowl with cold water (best done ahead of time if you think this might happen) and take the pot briefly off the heat when it sputs. Plunge the bottom half of the pot into the cold water, making sure not to submerge it so far that the water might get in through the seal between the two halves of the pot. Take it out of the water right away -- just a quick plunge and out -- and put it back on the heat. This will often jolt it out of its bad behavior, and a moment later the coffee will come out properly. This works best when you have the pot mostly working well, and just have a bad day.
posted by redfoxtail at 3:50 PM on February 5, 2008

I have almost the exact same one. Putting too much coffee in (and hence tamping it down) is bad, but I usually remove it from the heat as soon as the top bit is full (mine is pretty obvious from the noise). I usually have full power on, but if I'm shaving as well as showering (and so will be away longer) I use 3/4 heat and there isn't much of a discernible difference.

Don't underestimate the possibility of a bad batch of coffee, mind you. That's happened to me more than once. Throw it out and try another one, as I've not noticed much difference with modifying the procedure. These things are made to be filled and stuck on the stove top until ready. There should be no need to dick around with it unless there is something wrong with it.
posted by Brockles at 4:36 PM on February 5, 2008

I have found that the variable that most affects coffee made in a stovetop moka pot is how packed the coffee grounds are. Packed too tight, for me = burnt taste. Packed too loose, for me = acidic and weird. I've never noticed much difference in how or when I took it off the flames.

I know you said that your method has not changed, but perhaps the new filter plate you installed is different (smaller/larger/more/less holes) than the previous, and so your grind/packing has to change to compensate. Ditto for the rubber ring.

And speaking of, you might try boiling that new rubber ring for a bit, maybe that'll help toughen it up for it's new job of making your pot go bubbly without imparting a latex taste. But I've never tried that in particular, so I don't know if that'll work.
posted by gyusan at 4:46 PM on February 5, 2008

I used to have that exact pot but then I upgraded to the stainless steel moka pot, which is much much much better. ::hugs moka pot::
The way I brew in the stainless pot may help you, though.
--Put water on to boil in a teapot.
--While it's boiling put your coffee in the moka pot basket. Leave it out of the bottom of the pot, though.
--When the water is boiling in your teapot, pour it into the bottom of the moka pot, to the same level you would if you were starting with cold water.
--Put the moka pot together like you would normally. This will require a potholder and some finesse. It gets easier each time you do it!
--Put the moka pot on to brew as normal. If you have a gas stove don't turn the flame up to high. Let it brew over a low flame so the heat doesn't boil the coffee that come through to the top. I found that this was the worst problem I had. Boiled coffee is never ever a good thing.
posted by hecho de la basura at 5:03 PM on February 5, 2008

I think you're overheating it. It's a common problem - too hot an extraction pulls out more of the bad tasting compounds that you don't really want in your coffee (and more caffeine too), and gives a really nasty bitter taste, and thin, acidic consistency. You really don't want the water to get to a fast boil.

Personally I never had 100% satisfactory results with a moka pot, but I got my best results by heating on a low-ish temperature (and I think filling the base with already hot water to speed the process up is probably fine), and watching the pot carefully. At the first sign of coffee coming through, I'd turn the heat down as low as possible (you may need a diffuser on a gas hob top), or even sometimes remove it from the heat momentarily. The goal is to try to keep the the water around 100 degrees or slightly below, while still keeping the nice, slow flow of coffee coming through the spout.
posted by bifter at 2:26 AM on February 6, 2008

Here's what I do every morning:
  • 'Wash' the coffee maker. This is a hot water only, no soap process. The first year I was here, my flatmate caught me using soap and had a hissy fit. I learned you want your coffeemaker to be seasoned, much like a cast iron pan. Occasionally to get major calcium residue off the reservoir, I'll use a clean metal sponge along with the water.
  • Pour cold water in the reservoir, just under the little metal rivet. I use tap water here, but Evian when visiting the folks, because the tap water there is just foul./food snot
  • Put in the basket and gently heap in my coffee of choice. As mentioned above, don't tamp it down. The coffee should form a triangular-ish mound about 1, max. 2cm above the rim of the basket.*
  • Remove any fallen grounds from the threads & tiny lip edge of the basket & screw on the top. Make sure it's on good & tight.
  • Place on high heat. I have a gas stove, so I turn the flames up enough so that they're inside, but not too inside, the bottom edge of the pot.
  • When the coffee starts to slink out of the percolator, with that yummy crema look, turn down the heat slightly.
  • Once you start to hear that sucking sound, and the pot is pretty much at capacity, take it off the heat. It's done, you don't want it to burn.
New coffeemaker or parts:
  • You should make a few batches of hot water, say 5. After that, do the sacrifical batches of coffee. I remember the last new pot I had took me ages to 'break in', but the last time I had to replace the gasket, the water then coffee trick seemed to do just fine.
*Warning: I eyeball this, and I suck at measuring.
posted by romakimmy at 4:42 AM on February 6, 2008

Response by poster: I replaced the gasket this morning and made a pot, which tasted just like old times. (Ah, coffee.) I'll know in a week if this is a bad batch of gaskets. Thanks, all.
posted by Blazecock Pileon at 12:34 PM on February 6, 2008

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