Effects of Grind Precision on Beverage Quality

By David Miller, Latté 911 Commercial Espresso Systems

If you own a café that prepares specialty-grade coffee, you are probably getting accustomed to having account managers who not only supply coffee, but train and educate you on how to make money with it. Coffee scoring above 85 on the Q sheet is a sophisticated product, and building a viable business on it takes a lot of sophisticated knowledge and equipment. As technicians and servicing dealers, we have a unique set of qualifications in being able to train and educate our customers on how to run and grow their businesses more successfully, and key to connecting those qualifications to our customers is in understanding their point of view and the standards to which they measure and benefit from our equipment.

It’s generally agreed nowadays that if you’re featuring 85+ graded coffee in your shop it’s good practice to brew it to a fixed ratio using mass over time as a guideline; for instance dose/dry weight of 18g ground coffee to 36g yield/beverage mass over 27-32 seconds. The hard part is that 99% of espresso grinders make it very hard to run a service this way and one such obstacle is heat[1].  As a grinder heats up during service, the heat transferred to the coffee partially melts the soluble compounds in it, causing shots to pour faster. Grinding finer to compensate doesn’t solve this problem because heat has changed the solubles that are coming out into the beverage and thus changed its taste. So by managing temperature shift in the grinder you can affect a big improvement in quality consistency throughout the day and make it more practicable to brew to ratio. Another issue is exit speed of the grounds, which if too fast can cause excessive static or if too slow can cause binding, clumping and overheating. Some grinder manufacturers have addressed these issues on the design side; but as technicians we also have a key role in this.

Of course the standard response to the question of grinder maintenance is to keep it clean and observe regular burr blade changes. But managing heat in a grinder will have a positive effect on cleanliness and how long the burrs last. For instance, has the grinder been sized appropriately to the task it has been asked to do? If the client has one Super Jolly feeding three busy group heads, it might be time to quote them a Robur or two and delegate the Jolly to decaf duty. What about the quality of the beans, are they sweating oil on the hoppers/burrs/throat of the grinder and causing a sanitation issue? Finally, is your customer aware of how to properly care for and manage heat buildup in their grinders? Our customers are looking more and more to the support industries for training, education and assistance on how to make their cafés more profitable, and understanding the big picture is always good business.

Life Span Based on Manufacturer Recommendations

Compiled by Kaleb Leach

Bulk Coffee Grinders:

Bunn: 40,000 lbs

Fetco: 40,000 lbs

Ditting 804: 15,000 lbs
Ditting 1203: 25,000 lbs
Ditting 1403: 35,000 lbs

Mahlkonig K30: 1,800 lbs
Mahlkonig EK43: 14,300 lbs
Mahlkonig 1 Phase: 22,000 lbs
Mahlkonig 3 Phase: 22,000 lbs
Mahlkonig Guatemala: 11,000 lbs
Mahlkonig Kenia: 5.500
Mahlkonig Tanzania: 8-10,000

Espresso Grinder:

NS MDX: 800-1,000 lbs
NS Mythos: Titanium- 3500 lbs // Stainless- 1200 lbs

Mazzer Major: 1,300 lbs
Mazzer Mini: 660 lbs
Super Jolly: 880 lbs
Kony: 1,322 lbs

Swift: 3,300 lbs

Azkoyen: 800 lbs

Fiorenzato: 700 lbs

Rossi: 700 lbs

Rocky: 600 lbs

Capresso Infinity: 400 lbs

Baratza: 200 lbs

[1] Generous technical assistance provided by Tamper Tantrum/3FE Coffee/Has Bean Coffee Ltd.