When I make coffee with my Bialetti, there is a bit of coffee grounds in my cup. Is the coffee too thin ? On the package is written that it is fine for the Bialetti machine.
3This is possibly because of inconsistent grounds. There may be finer grounds. This is common and @ecnerwal ’s answer probably solve the issue. However, finer grounds may make your cup a bit more bitter. Observe this. Have fun.– MTSanMay 27, 2017 at 7:35
The reason is that your coffee grounds are too fine. Your Percolator needs coarser grains for various reasons:
- Allowing water trough it more easily – else the pressure needs to go too high and your coffee will taste burned as it is roasted a second time from the overheated filter basket .
- Not allowing small small grounds to "whirl" up in the water and reach the top  and flow into your final coffee.
In addition to this and if above does not help, you can —if needed— still go with what @Ecnerwal suggested as a last ressort.
 You can avoid a good part of this by using very warm (non boiling) water, instead of cold water. This means the water will boil earlier and the grounds will not get exposed to too much heat over a longer period of time.
 Do not over–power your stove. When I cook my coffee, I turn the (electrical) stove to between level 7–8/12. Using a lower heat not only makes the coffee drinkable and removes a lot of the overly strong and often bitter taste, but also prevents smaller grounds to whirl up as the water has less energy, moves less and allows smaller grounds to sink back into the filter again.
, should this be cold water heated in a kettle? and how hot should it be? Jun 11, 2017 at 21:03
2Well, hot water is hot water and it does not really care where it got hot – thats pysics, not religion ;) I use water from the tap, probably 60 degree hot as I limit it with 70 in the house installation. I would believe keeping it around 90 might be good to get it to the grounds as quickly as possible.– kaiserJun 11, 2017 at 22:11
Sorry I know this is an old thread but I'm commenting because I found this looking for some moka pot info. You don't want to use hot water from the tap. Hot water more readily dissolves solids than cold water, so hot water from the tap will be "harder" than cold water from the tap (higher TDD or total dissolved solids) and will not extract your coffee as well as cold water would. Use cold water from the tap if you have soft water or water from a Brita type filter if you have hard water, then heat it in an electric kettle. Pour the hot water then into the bottom of the percolator.– R MacAug 15, 2019 at 13:45
@RMac Why would I need to heat it in an electric kettle, when I can get hot enough water from the tap? In the end I got hot water to fill in the bottom of the percolator, right? Reason I use hot water at all: Get the water as fast as possible to the freshly grained beans. Also, and that might only be my taste, I like it that the coffee tastes smoother when I use hot water.– kaiserAug 21, 2019 at 7:54
Hot water picks up solids from the pipes it travels through better than cold water does. You want low TDS water for brewing coffee. You can buy cheap TDS testers online. Unfiltered tap water in general falls between 100 and 400 ppm TDS, and ~150 ppm is ideal for coffee extraction. You'll likely get closer to 150 ppm using cold water than using hot water.– R MacAug 21, 2019 at 14:11
You can always pour through a paper filter (after brewing by whatever means) if you want to avoid any grounds in the cup.
Don't worry, you've taken your first step to solving the problem. :)
If you find grounds in your cup, and you grind your own beans, simply grind your beans a few clicks coarser on your next brew.
But if you've already purchased a bag of ground beans, then try to have them ground a few clicks coarser next time. :) You'll get your clean cup real soon!