I've just bought a moka pot for the first time and have been practising with it all this week. It is a really cheap thing that I bought for £7; would have preferred a bialetti. My method is improving but I've still got one problem.... My moka pot was specified to make 6 espresso-cups of coffee but on my first few times I only achieved 4-cups and just the last time only 3-cups. Are there any common mistakes that I could have made? The last time I used it, there was quite a lot of water left in the bottom but I took it off the stove because it was spitting a lot and nothing was actually flowing.

Thanks.

Hello - perhaps a silly question, but what volume are you using to measure a "cup" ?

There does seem to be quite a wide variance between manufacturers in matters such as how much coffee grounds these types of pot hold versus their published nominal cup capacity. They tend to be a bit inconsistent in the volume you get out, but 1/3 more on some occasions is a lot more than I'd expect.

I assume you are filling the base to just below the safety valve and not tamping the grounds - just sort of smoothing the top of the coffee - and that you are using the same coffee, same amount, and same grind level each time ? Also, when the coffee starts to flow, that you are turning down the heat to give a nice steady flow.

There will - and must be - some water left in the base after brewing.

Next time you use the device, measure carefully (put it on gram scales) how much water you are putting in, measure carefully how much coffee you get out, and when cooled, how much water is left in the base.

There are some other considerations, such as how much water remains in the grounds, but I'd measure these things first.

Does it taste OK anyway ?

I'm just using a gaggia espresso cup as a reference.

Yeah, I try to fill it about 3mm from the hole of the valve each time. There is a small variation in the amount of coffee I use and I haven't quite refined my temperature regulation so that's a little too sporadic but I do turn it down a little; I'll try to keep these constant.

Yeah, it taste quite good considering I've been using cheap and probably stale pre-ground espresso coffee because I'm waiting till my hand burr-grinder arrives to use the beans I have in the house at the proper grind level.

I'll try it again with the measured water and coffee soon and report back!

Thanks.

The standard definition for an Espresso (Italian standard anyway) is 25ml +/- 2.5ml for a single cup. This is a lot less than many people think.

Using espresso cups themselves to measure is a bit hit and miss. Most are designed at least to hold a double (50ml) and many have a maximum capacity of up to 100ml.

Would be worth doing an accurate measurement of your "cups" using gram scales.

I've started using a higher initial temperature for my moka pot and the water level problem seems to be resolved. I'm going to slowly adjust the grind and temperature and see if I can improve it further. Thanks guys.

In my experience, beans that have been pre-ground for espresso is too fine for the moka pot. Your grind is too fine if the flow is slow and strugling and you get spitting.
I get good results with pre weighing my beans so I use the same amount everytime or I can make adjustment. I also use just off boiling water to 1mm under safty valve, then staight onto low-med heat. Once I put the pot on the stove it takes a couple minutes before I see coffee coming out and when I do i reduce the heat or turn it off. I never let it get to the point where the stream is really light in color or it's spitting. If you leave it on for that long, you're burning your coffee. Once I'm satisfied with the amount, usualy a cm or two off the bottom of the V under the spout, I lower the bottom half in a bowl of cool water to stop th brewing process completly.

Cheers!

Curiously, you do not identify exactly which brand of pot you are using.

I have found, to my amazement, that performance does vary among various brands of pots despite the seemingly foolproof basic design. My completely unsupportable guess is that a large number of people will use coarser than espresso grounds out of naivete, not really being able to tell the difference. Those that manufacture cheap and less functional pots make a buck off of this market segment and don't care what the cognoscenti think about them.

I can offer a reference for grind: Peet's shops use identical grinders; their settings are:

#1 Turkish, i.e., powdered.
#2 regular espresso, or fine espresso, as used in professional barista espresso
#3 stovetop or Bialetti or moka-pot or coarse espresso; what we are talking about in this discussion.
#4 medium or Melitta/Chemiex for pour over percolation that depends upon gravity for the water to penetrate the grounds
#5 coarse for French press and old fashioned percolators

The following is based on my experience with 6-cup Bialetti (classic aluminum and 2 different stainless) and the current and previous IKEA stainless models.

Using #3 grounds, you can heap them above the rim of the funnel and pack SLIGHTLY by gently dropping the funnel on the counter or tapping its side with a spoon, and these pots will work. I do this in order to get maximal strength brew which I crave. You will have to perfect your technique via trial and error if you push the limits as I describe here. Packed too tightly the water will simply vent through the valve (in best case) and not percolate (yes, percolate) through the grounds. You can blow off an entire tank this way. If the valve gets clogged the pressure will blow the carafe off the tank, cross-threading in the process. I do know this...

One compensation, if all the water is escaping as steam, is to stopper the valve with e.g. a pot holder to increase pressure, which can get your hands very hot, and scorch the pot holder.

Defective designed pots will, for some reason not clear to me, allow the grounds to pack too densely(?) at the top of the funnel for the water to percolate; when this happens the steam seeks equilibrium by traveling directly THROUGH the water, up the funnel, THROUGH the grounds and out the pipe, steaming the grounds but creating no beverage. That is, instead of PUSHING the water through the grounds, the steam FLOWS through the water. A minimal amount of beverage may be brewed before the water flow stops. From your description I would guess this is what's happening.

If you use less than a fully packed funnel, and/or coarser grounds, you will get (with the above pots) simply weaker coffee. I must emphasize that I have made good coffee in a stainless 6-cup Bialetti with a full tank of water and HALF a funnel of grounds, for my friend who does not share my preference for super-strong coffee.

Depending upon how densely you pack the grounds, a 6-cup 350 ml tank will yield about 300 ml of coffee; a lot escapes as steam under normal conditions.

Interested to hear how yours is doing.