This is one of those questions where there’s already a fairly good consensus about which one is better. The short answer is that, if you can, go for a coffee grinder which uses burrs. Though if it’s a choice between a blade grinder or pre-ground coffee, the blade grinder will still offer value.
Why is that? Well, as soon as the coffee beans have been ground up, they begin to lose their flavor and become somewhat stale. So this means that the pre-ground coffee that’s being sold in shops or stores has already probably had weeks or more to become stale. That’s not something you want to start with if you’re looking for the best coffee flavor possible. As much as possible, you want to grind your coffee immediately before you plan to have your cup.
Now, as far as burrs and blades are concerned, there are a few problems with blade type grinders that burr grinders are able to avoid. One problem is that the way in which blades do their grinding is rather uneven and unpredictable. As the blade spins, it begins to chop up the beans into smaller and smaller pieces, as you endeavor to get the grind you want. But what people usually end up with is a grind where some particles are finer or coarser than others. This lack of uniformity is a key problem, and could cause problems with your coffee maker.
Then, there’s also the issue of heat. In order to get a finer grind within a set period of time, the blade usually has to spin faster. The problem though is that this motion generates heat, and if there’s enough of that, you can end up with coffee that has something of a burnt taste. This potential deterioration in flavor is another reason many coffee lovers prefer burr grinders.
The burr grinding mechanism does away with these problems. You’re able to come up with a uniform grind each time, and it’s more possible to have greater control over just how fine or coarse you want the resulting coffee to be. This means that whether you’re preparing an espresso, or using a French press, you can achieve the particular grind that you desire and that works best for that specific brewing method.
As far as the issue of heat is concerned, it’s still possible to burn the coffee using a burr grinder. But to counteract this, there are burr grinders which are designed to work at low speed. This means that you are still able to come up with the grind that you need, but with less or no risk of generating excess heat and burning the coffee.
That said, many of the less expensive grinder do use blades. So again, if it’s a choice between an inexpensive blade grinder or no grinder at all, the blade grinder will still be a step up. But because of all the additional benefits that come with a burr grinder, it does make sense to aim for that if possible. After all, if you make the effort to purchase good coffee, you need to run it through a grinder that preserves that high quality taste. Here are some of the best sellers in the burr coffee grinder space.