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The strange white growths inside my espresso maker

  • h

Call me ignorant. My husband and I just purchased a nice espresso maker - the traditional Italian type that can be purchased anywhere and is composed of three parts that sits on the stove top and percolates water through a sieve filled with coffee into a container at the top. What is it that is found gathering in the lower part (that you fill with water) after its been sitting around for awhile? My husband suspects its mould but I think its probably mineral/calcium deposits from the boiled water. An Italian told me never to look in there or clean it, but I just can't help myself - it looks too suspect. Thoughts from experienced espresso lovers please...

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  1. It is almost certainly mineral deposits, not mold. There are commercial cleaners available, or you can use an abrasive if you can get into the space.

    2 Replies
    1. re: AlanH

      I think vinegar (white) will do the trick

      1. re: AlanH

        Run a pint of white vinegar through the brewing cycle. It works well in drip coffeemakers, too. Makesure to run a pot of water afterward before making a pot of coffee.

      2. Try soaking or boiling them out with plain old distilled vinegar, or a mixture of sour salt (found in the kosher food section of the market) and water (1/4 cup sour salt to 8 c water in a regular coffee maker - adjust proportionately)

        1 Reply
        1. Dear Ignorant,

          Those deposits are really nothing to worry about. They are just mineral deposits and do not affect the taste of the coffee (after all, they are sticking to the pot rather than leaching into the water--in fact, they are being leached *out* of the water, it seems to me). They would be a problem in an electric espresso maker, where they could restrict the flow of water through the system, but in the pot you have it does not matter.

          1. I'm guessing that the type of espresso maker you've got is made of aluminum. The top and bottom are flared and faceted, right? with a little black plastic peg-like thing on top? The mineral deposits are harmless, but they are the result of aluminum being a "reactive" metal, that is it mingles, in a microscopic way, with the stuff you put in it: coffee. A stainless steel espresso maker (also inexpensive but not quite so inexpensive) will never develop these deposits.
            Good luck.

            2 Replies
            1. re: Erica Marcus

              I use a sponge on a stick to wipe out the inside of the coffee maker. Never put it in the dishwasher. Don't worry about the deposits, they won't hurt you or the coffee.

              A friend asked me a bunch of questions about how to make cuban coffee in the italian espresso machine. Here are my responses. Warning: cuban coffee is extremely addictive.

              Q: Do you need to use Cuban coffee or does espresso roast or Jamaican work just as well?

              A: I have had the best results with Cuban coffee.

              Q: is there a brand you prefer?

              A: Bustelo Supremo is the best (black can). Regular Bustelo is good. You can find it in Mexican markets.

              Q: How finely do you have it ground?

              A: Very fine, almost powdery. (if you buy a can of either bustelo, you will see)

              Q: What is your ratio of scoops of coffee to water.

              A: What size machine do you have? I have the 4 cup maker and I fill it so that the water goes halfway up the screw on the side. I fill the coffee recepticle with grounds and tamp it with the weight of the spoon.

              Q: For brewing, do you low or high heat?

              A: High heat, but be careful with gas, i accidently burned off part of the handle one time.

              Q: I have read a couple of articles on mixing in sugar and creating foam. What is your technique?

              A: This is the tricky part. For a 4 cup maker, use 4 to 5 tsp of sugar. Put the coffee on to brew; put the sugar in a measuring cup; leave the lid of the machine open while the coffee brews; right when the coffee begins to brew, add about 1/2 to 3/4 tsp of the first drops of coffee to the sugar (too little* is better than too much**); use a spoon to mix the coffee/sugar together to a paste; keep mixing while the coffee finishes brewing; add the rest of the coffee and stir so that the paste is completely incorperated. It should look like guiness.

              *If you add too little liquid at the beginning, you can always add a bit more coffee so that all of the sugar is dissolved.

              **If you add too much, add sugar until it thickens, and then scoop out some of the sugar paste so that the coffee isn't too sweet. you sort of have to eyeball it.

              The paste is the key to good cuban coffee. if you do it right, you will get a thick foam and rich/sweet coffee. do it wrong and you will have sickly sweet watery coffee.

              1. re: Dan Raffle

                how about the fabulous cafe con leche? techniques?

            2. Just scrub the the inside with SOS or some such, rinse very well, and dry. It'll be good to go next time you want a cup of espresso. I've been using the same one for many years!

              1. I've been worrying about this over the past months, as I also have one of those aluminum espresso makers. Would those aluminum salts be harmful over a period of years, do people in Italy get some rare disease related to increased ingestion of aluminum salts from their espresso makers? Then I just go and wash out the inside and make an espresso.

                1 Reply
                1. This is the reason I bought my stainless steel Bialetti. The aluminum one just icked me out too much. I LOVE my new one!

                  1 Reply
                  1. re: Becca Porter

                    I've also seen nice enameled aluminum ones which would probably be healthier.

                  2. I have experienced this same thing many times, and just could not stand it. I tested several moka pots, and can tell you that this only happens with aluminum, and under a specific circumstance: sealing up the pot while there is still moisture in it.
                    Getting rid of the gross white stuff was easy enough: wipe it out, then run plain water through a cooking cycle. Empty the pot and wipe it out again. At this point, it's essential to let the individual pieces air-dry before reassembling. When I was using the aluminum pot each morning like clockwork, I rarely even bothered to assemble it and put it away. I would often just rinse them after use and let them sit upside down on the drying rack until the next day.
                    If you use your pot only occasionally, I suggest you allow the parts to dry well before putting them back together. Pay special attention to the basket- you will need to shake the water out of the little holes a couple of times (I used to tap it against my hand and would invaariably feel drops of water flying out, even hours after washing).
                    I eventually became really compulsive about the whole thing, and constantly having a disassembled coffee pot out on the counter became bothersome to some. I finally made the switch to stainless steel about one year ago, and can honestly say that I do not detect a difference in the quality of the coffee (believe me, I looked for it). Aluminum is more traditional, and sometimes I do miss my old pots (I kept them along with a family collection dating back to the '50s), but the stainless is definitely lower maintenance.
                    What the Italian person said to you about not "looking in there" is pretty funny. I, too, believe that over-cleaning the pot is a bad thing, and would never recommend you use any kind of cleanser, or even vinegar. But not looking in there? I don't know- I just couldn't stand knowing it was there!

                    3 Replies
                    1. re: vvvindaloo

                      the aluminum is faster/slower than the stainless? you will find this about aluminum bialetti of interest, i believe:

                      1. re: alkapal

                        Thank you! i really enjoyed that article and am printing it out for my mom as i type :)
                        No, I haven't really found a big difference in cooking time. I always cook mine very slowly, as I find it results in a thicker, richer cup. I'd say it takes about the same amount of time.
                        Thanks again, alkapal.

                        1. re: vvvindaloo

                          glad you liked it. i thought it was insightful.

                    2. As others have said, the white growth is simply harmless mineral deposits from the aluminum reacting with the water.

                      But I see many other people recommending that you clean them out somehow. I've been having a problem with this because my coffee develops a metallic flavor. Again, harmless, but not tasty.

                      Wikipedia's maintenance section (http://en.wikipedia.org/wiki/Moka_pot...) indicates that the oily coffee residue can prevent this metallic flavor, but that oil never reaches the bottom chamber.

                      I'm wondering about using distilled/reverse osmosis water (heard mixed reviews), and about perhaps putting a little coat of some kind of oil in the bottom of the pot. I'll report back if I remember to.

                      1. easy experiment -- are the white things hard and gritty? mineral deposits

                        soft and squishy or maybe even kinda slimy? Mold.

                        Probably mineral deposits, as there's really nothing there for mold to survive on.

                        1. How often do we look inside the teapot, rather than the coffee maker? When my Mom occasionally has the teapot dry out over a low burner horrible stuff comes out when washing it!