Coffee Grind Time and Caffeine: Is There a Connection? New Research Says Yes!

Or Alternate Title “42: The secret to life, the universe and a strong cuppa” HT: Douglas Adams

By Michelle Z. Donahue

SPECIAL TO BARISTA MAGAZINE

If you’ve ever wondered how long you should be grinding whole coffee beans to get the max amount of caffeine in your morning joe, you now have the ultimate answer.

Inspired by a former co-worker who used to grind his beans for what seemed like a œridiculous amount of time,  Christopher Murray and Thamara Laredo decided to settle the question once and for all: how long do you need to grind to get a good, strong cup of coffee?

Murray and Laredo, both researchers in the Department of Sustainability Sciences at Lakehead University in Orillia, Canada, recently looked into this very question and came up with 42 seconds. That’s the magic number to get the strongest cup possible out of even a relatively small volume of beans.

œPeople would shake their heads, listening to him grinding,  Murray said of his former colleague, laughing. œHis intention was to make the coffee so strong the spoon would stand up in it. I didn’t know if he was crazy or not, but I wanted to see if there was anything to it. 

For their experiments, Murray and Laredo used electric blade grinders, primarily because of cost: they figured that more people probably have blade grinders simply because they’re less expensive than burr grinders. Working in time increments from zero (whole beans) to a whopping 84 seconds of grind time, they ran about five tablespoons of samples through a Black and Decker percolator then analyzed the extracted caffeine in a spectrophotometer. They also compared their results against decaffeinated beans, which matched up with whole, unground beans.

Grind experiments have been conducted before, but hadn’t explored a full range of possible grinding times to see exactly how much caffeine gets dumped into a 12-cup pot of coffee. The standard time recommendation for grinding beans is 10 seconds. But when Murray and Laredo added another 30 seconds, what they found surprised them: the caffeine content increased by 100 percent.

œYou would expect that it is more, that you’d get more caffeine the finer you grind, but to get twice as much, that was kind of surprising,  Laredo said. œBut you have to go a long time ”I don’t think people in their right mind usually go that far. 

Try it, and you’ll quickly see what she means: stand in the kitchen with the little grinder buzzing for more than half a minute, and even 20 seconds begins to feel just silly.

To make sure it wasn’t a function of how long the water took to pass over the grounds, the two researchers tested the caffeine content of coffee that took five minutes to brew and compared it with coffee that was left to stand with grounds for 20 hours. The caffeine content didn’t change, so they concluded that the increased caffeine could only be accounted for by the size of the coffee grounds themselves. The finer the grind, the higher the level of caffeine, no matter how long it took for the coffee to brew, or even how much water the grounds themselves absorbed.

Interestingly, any additional grinding after 42 seconds didn’t increase the caffeine content, though Murray warned that grinders tend to get a little hot after such an extended milling session. Plus, there’s the awkward sensation of just standing there for so long.

œThere’s a limit to how long you can press that button before you start to feel insane,  Laredo added.

And if you don’t feel like counting to 42 every morning just to annoy your office mates, you’ll probably get close to the full effect if you settle for grinding your beans for a mere 30 seconds.

Plus, you’ll make a bag of coffee last that much longer.

The results of the study were published in the February 2015 issue of the Journal of Food Research.

ABOUT THE AUTHOR



Michelle Z. Donahue is a journalist and freelance writer who often writes on quirky science and the natural world. A graduate of Vanderbilt University, Michelle lives in Maryland with her husband and two children, who do their part to help harvest green beans from the garden in summer. One of her favorite DIY experiments was roasting green coffee beans in a hot air popcorn maker, which made the yard smell an awful lot like the German konditorei of her youth.