I'm thinking about buying a moka pot.
I have a blade grinder.
Will a blade grinder grind coffee beans fine enough for a moka pot?
I can't really afford an expensive grinder and I don't want to use pre-ground coffee, because I heard it loses quality quickly.
Yes, you can, as long as it's a decent quality blade grinder. It's how I fill my moka pot, which I've been using 5 days a week for the last 4 years.
You can't do actual espresso in a blade grinder (it's not possible to get the grind consistent and fine enough). But moka pots are a lot more flexible in the grind of coffee that they will accept. Just grind it almost as fine as you can -- this takes about 30-40 seconds of grinding in mine -- and put it in the basket.
Yes, a (decent quality) blade grinder can do an acceptable job at a fine grind.
Blade grinders don't do well at coarse grinds: if you try you generally get a very uneven grind. But for find grind, you run it longer and generally get a sufficiently even grind. You don't have the same degree of control over the grind as with a burr grinder, however. You have to experiment with how long to run your grinder for a given quantity of beans. You also have to be careful not to run it too long and overheat the beans.
I like to drip coffee and use a blade grinder because it was cheap and I don't mind if the taste is somewhat more bitter than it would be with a coarser grind. I use about an ounce of beans and grind it for 12-15 seconds.
