Blade grinder vs. single mug?

Question

For "utility" coffee drinking, I temporarily need to grind coffee with something as inexpensive as possible, and would prefer something with a motor. My understanding is that fresh beans ground with a blade grinder at brewing time will still be significantly better than old ground coffee. So I'm looking at inexpensive blade grinders, and have a question about blade design.

On some models, the blades sit fairly high off the base of the grinding cup (these are sold as coffee grinders, not general purpose grinders). They are advertised as handling enough beans for 10-12 cups. With that amount of coffee, the grounds will push each other around and mix in the cup. However, I'd be grinding just a couple of coffee measures at a time.

Here are a couple of pictures from the product information for one such grinder (Proctor Silex 80402):

_Source

In the first picture, you can see the large gap below the blades. The second picture shows some small amount of ground beans sitting completely below the blades.

It looks like for a small amount of coffee, the beans would quickly break up into chunks small enough to drop below the blades. Then they would pretty much just sit there and not get ground finer as the blades spun above them.

I'm wondering if people here have experienced that problem with blade grinders of a similar design, or would even a couple of measures of coffee be enough to go well over the top of the blades, so the grounds do mix and circulate?

If anyone doesn't want to admit on the site to using a blade grinder, feel free to preface any answers with "I read somewhere..." or "Long, long ago before I knew anything about coffee...". :-)

Answer 1

From personal experience the blade grinder moves the air around the beans enough to get a smaller amount moving, but if getting everything ground to consistency is the goal, I found that shaking the grinder while it's grinding helps quite a bit. Something that also helped was to pulse the grinder off and on instead of holding it on for the duration of the grind. It took some experimentation to work well, and even then it was still a cheap grinder, but it'll get the job done for sure.

Answer 2

Further investigation indicates that this varies by model. For example, Proctor Silex says the model listed in the question has a minimum of 1 tablespoon. The user manual for a number of KitchenAid models specifies beans for 4 cups of coffee minimum.

Krups makes a "Silent Vortex" model that sounds like the wind from the blades is used to stir things up, as Crab2215 described. Even with that, its user manual describes some minimum quantities (beans for 3 cups of coffee in one place, 2 tablespoons of dry material in another). Someone asked about this in the Customer Q&A on Amazon, and the manufacturer replied:

...if your grinder is filled less than the recommended amount it may cause damage to your grinder as well as malfunctions.

So it sounds like there is probably some minimum amount of material for blade grinders to work correctly, and that amount varies by model (and is not typically described in the advertising). The take-away is that if you plan to use a blade grinder for small amounts, like grinding beans for a single cup of coffee, check with the manufacturer regarding minimum material, or look up the user manual online before purchasing it.