What to Do When Your Coffee Grinder Gets Stuck? How to Fix an Espresso Grinder That Won't Dispense Coffee? Espresso Grinder Adjustment Logic!

"Adjusting espresso" is a workflow that gives every morning shift barista a major headache. The difficulty of dialing in doesn't entirely depend on the barista's experience level, but also on the condition of the beans and the weather's influence. Even a seasoned coffee veteran might sometimes waste most of a bag of beans adjusting the grind due to these factors. Therefore, this is a task that somewhat relies on luck.

Today, with sunny weather and beans in good condition (because they had been properly aged), surprisingly, a colleague with many years of deep experience in the coffee industry sent a distress signal to FrontStreet Coffee. The reason was simple: after adjusting the extraction parameters several times, the coffee remained "stubbornly defiant" and tasted unpleasant!

According to the colleague's description, despite multiple extractions and several grind adjustments, the coffee's extraction state and taste showed almost no change. After FrontStreet Coffee went over to investigate, the issue was immediately identified. Suddenly, FrontStreet Coffee had an epiphany: perhaps sometimes when we can't dial in espresso properly, it's not really that the beans are difficult to adjust, but rather because we've overlooked an important factor, leading to a lot of "wasted effort." (Regarding how to dial in espresso, FrontStreet Coffee has already explained in detail in the article "How to Quickly Dial in Espresso" - here we're discussing one major reason that might make us waste half a bag of beans.)

What Factor Causes Us to Waste Effort?

The reason we need to adjust the grind when dialing in espresso is that the extraction efficiency isn't up to standard. Therefore, we need to change the coffee particle size through grind adjustments, which in turn affects the extraction rate. Generally, each adjustment of one notch will bring about a 3-5 second change in extraction time. For example, if we originally used 20g of coffee to extract 40ml of liquid in 24 seconds, after adjusting one notch finer, it would become 20g of coffee taking 24+3-5 seconds to extract 40ml of coffee liquid.

But if there's no change and it still extracts 40ml of coffee liquid in 24 seconds, then we need to observe the grinder's dispensing state. Because when the flow rate remains unchanged despite changing the grind, it means the grinder's burrs haven't adjusted accordingly. This likely means the grinder is—clogged with grounds. The cause of this clogging is quite common: it's due to "static electricity." During the grinding process, coffee grounds easily generate static electricity due to constant friction, and static electricity gives coffee grounds adhesive properties. This adhesion can cause coffee grounds to stick together and clump, or it can make coffee grounds adhere to other objects, affecting them. The grinder issue mentioned above occurs because coffee grounds adhere to the burrs and dispensing outlet, causing blockages that affect grinding precision. Even if you change the grind setting, the grinder still produces coffee grounds of the same fineness. (Inside the grinder's dispensing outlet)

The deeper the roast level of coffee beans, the finer the grind, and the drier the grinding environment, the more easily static electricity is generated. And coincidentally, espresso grinders almost completely meet all three of these conditions: coffee beans are typically medium-dark roasted; the grind is as fine as flour particles; and grinders are usually placed next to espresso machines, whose emitted heat reduces environmental humidity... You could say all the buffs are maxed out... But even so, these conditions combined would at most cause coffee grounds to clump, not necessarily lead to situations where coffee grounds clog the grinder. Generally, there's only one reason why this kind of clogging occurs: when we empty the grinder and grind a very small amount of beans.

When we need to change beans or adjust the grind, we usually empty the grinder. But at this point, there are always some residual beans in the grinder that are difficult to clean out. I believe many people, like FrontStreet Coffee, just grind them away. But it's precisely because of grinding these beans that the clogging situation occurs. Because these beans aren't subject to hopper pressure during grinding, they produce a lot of fine particles. And these fine particles, due to static electricity, adhere everywhere. When they adhere to the burrs and dispensing outlet, they naturally cause blockages. And as FrontStreet Coffee mentioned earlier, when this situation occurs, there's a very obvious phenomenon during grinding: "flying grounds." Normally, the coffee grounds we grind fall vertically from the center, whereas flying grounds caused by clogging, as the term suggests, cause coffee grounds to scatter in different directions. Wide dispensing range (clogged state)↓

Concentrated dispensing range (normal state)↓

If you're lucky and the blockage isn't too severe, we might be able to clear out these fine particles by grinding one more dose of beans, and the grinder's precision returns to normal. If you're unlucky and the blockage is more severe, then even if we keep grinding, the grinder will still operate at its original grind setting. The solution is actually quite simple and crude. We just need to take out a long spoon (or other thin, long rod-like object), and use the handle to poke from the dispensing outlet, from outside to inside. Don't use force—just gently tap to knock down the powder adhering near the burrs. Generally, when you poke around until no more fine particles fall, it basically means the problem has been solved, the grinder's precision has been restored, and we can start dialing in as usual. (It's best to operate when the grinder is unplugged or in a non-grinding state.)

Many friends overlook this point, which leads to wasting most of a bag of beans during grinding. Because no matter how you adjust, the grinder can't change its grind setting due to clogging, so naturally, you can't dial in delicious espresso. Besides paying attention to whether the grinder is affected by coffee grounds with static electricity, there's another point we need to note: it's best to clean the grinder burrs regularly. Because not only static electricity but also oils from coffee beans can cause coffee grounds to adhere and clog, affecting the grinder's grinding precision. And these can't be removed just by poking with a long rod. Therefore, setting a regular cleaning schedule can appropriately extend the grinder's lifespan and maintain its grinding precision~

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