A simple trick to make better coffee: cut the static!

 

You’d think that coffee afficionados had tried everything by now, and that few if any tricks remained undiscovered. Well, you could be right–but there’s one trick that most ordinary coffee drinkers probably don’t know, and it’s remarkably easy to do.

I’ll jump right to the punchline, and then I’ll explain the (new) science that explains it. To make richer coffee in the morning, simply spritz a little water on your beans before grinding them. That’s it!

So what happens when you do this, and why does it make better coffee? Well, as explained in this new paper in the journal Matter, by Christopher Hendon and colleagues at the University of Oregon, it’s all about reducing the static electricity that the grinding process creates.

Grinding coffee causes triboelectrification. If you’ve never heard of that, not to worry–neither had I, until I read the paper. Basically, when the beans rub together, they create static, and that makes the ground coffee clump together (and sometimes fly into the air).

Then when you make the coffee, the clumping means that the water flows through the grounds unevenly, absorbing less of the coffee particles than it might. Ideally, all the coffee grounds should be evenly and densely packed, and static electricity prevents that.

Water reduces triboelectrification quite a bit, it turns out.

So what happens? Well, after extensive experimentation–and I do mean extensive–the scientists found that the amount of coffee solids in a cup of espresso increased from 8.2% to 8.9% when adding a bit of water to the beans before grinding. That’s a relative increase of 8.5%. Richer coffee!

Reading the paper, I realized these scientists had a lot of fun doing these experiments. They measured the water content in 31 types of coffees, and tried a wide range of settings for their grinders, for the water temperature, and more.

They also roasted their own beans to varying degrees of darkness. They tried dozens of combinations of beans and roasting strategies, measuring the water content after roasting and the amount of static electricity generated upon grinding. They observed that darker roast coffees usually generate finer ground particles, and finer particles in turn generate more static electricity.

They drank a lot of coffee to get this right! But hey, sometimes science requires sacrifices, right?

I should mention that the trick of adding a little water to the beans is already known to some experts, although the precise science behind it was unknown until now. It even has a name (as the paper points out): the “Ross Droplet Technique.”

As the paper concludes, “a few simple squirts of water [may] have solved the problems of clumping, channeling, and poor extractions while aiding in the pursuit of attaining the tastiest espresso.” You only need a few drops of water–give it a try.

One important caveat is that if you use the French press method to make coffee, where the grounds are immersed in water, then this trick won’t make any difference.

What’s next? Well, I should point out that this study focused entirely on espresso. Does it work for regular coffee as well? Probably so, but more research is needed.

Does drinking coffee reduce the risk of atrial fibrillation? Maybe just a little.

Atrial fibrillation is the most common type of heart arrhythmia in the U.S. and Europe, affecting millions of people every day. A-fib is a condition where your heart beats irregularly and less efficiently than normal. Some people experience a-fib without even being aware of it, but it is a serious condition that leads to an estimated 750,000 hospitalizations per year in the U.S. alone.

The causes of a-fib are not completely understood, but one widespread view is that too much caffeine might trigger it. For example, the American Heart Association’s website says that “Avoiding atrial fibrillation and subsequently lowering your stroke risk can be as simple as foregoing your morning cup of coffee.” Although the site goes on to describe more substantial treatments such as beta blockers and calcium channel blockers, the idea of simply cutting out coffee seems very appealing.

As appealing as it sounds, this advice is wrong, at least for men.

In a study published in 2019 in the Journal of the American Heart Association, Vijaykumar Bodar and colleagues at Harvard Medical School looked at data from nearly 19,000 men who participated in the long-term Physicians’ Health Study. They looked at the risk of atrial fibrillation in men drinking anywhere from no coffee at all to 4 or more cups per day.

They found, somewhat surprisingly, that men who drank 1-3 cups of coffee per day had a 15% lower risk of a-fib compared to men who never or almost never drank coffee. They also found a small hint of a “dosage” effect, with the greatest reduction in risk at about 1.5 cups per day, and less benefit as consumption rose to 4 or more cups.

In a commentary published along with the study, Ryan Aleong and Amneet Sandhu point out that coffee contains a number of ingredients that might explain its cardiovascular benefits. They also point out, though, that the benefits are modest at best.

Unfortunately for women, though, coffee doesn’t seem to have the same benefits for them. Back in 2010, the Women’s Health Study reported that higher caffeine consumption did not increase the risk of a-fib in women, but it didn’t decrease it either. In a subgroup of women drinking the highest amount of coffee, they reported a slight increase in the risk of a-fib, but those women also smoked more often.

(Actually, if you look closely at the numbers in Table 2 of the Women’s Health Study report, women in the group who consumed an average amount of caffeine had a 20% lower risk of atrial fibrillation, consistent with the more recent study in men.)

For those of us who like coffee, this seems to be good news. At worst, coffee isn’t bad for heart health, and at best it might slightly reduce the risk of atrial fibrillation.

Some caveats: although these are large studies with thousands of men and women followed for many years, they rely on self-reporting of coffee consumption, which isn’t perfect. That’s probably the best we can do, though, since it’s impractical to measure caffeine consumption precisely over a long period of time.

The best advice, then, appears to be to keep drinking one or two cups of coffee per day, if you enjoy it. For those who have atrial fibrillation, cutting out that morning coffee, as the American Heart Association suggests, is very unlikely to help.

Relish that coffee now. It might be extinct in 20 years.

Most people think there are two major kinds of coffee, arabica and robusta. (No doubt some people think the two kinds of coffee are regular and decaf, but I digress.) And it's true that almost all the coffee that you can find in the market, or at your local coffee shop, is made from one of these beans or from a blend of both.

Actually, there are 124 species of coffee. Unfortunately, as we learned in a new paper published last week in the journal Science, 60% of them are currently in danger of going extinct. The primary threats are habitat loss (caused by humans) and climate changes (also caused by humans).

Even though the term "endangered species" is more often used to refer to animals, we humans have already wiped out countless plant species, primarily through deforestation, and many more are going extinct each year. We will never know how many species have already been lost as we've chopped down rich rainforests to create grazing lands for cattle or monoculture plantations, but we do know that it's still going on.

Of the two major beans that we use for coffee, the better-tasting bean, arabica, is already endangered, according to the new study. Robusta coffees aren't bad, but as the new paper explains:

"Although robusta has some negative sensory qualities (e.g., tasting notes of wood and tobacco), it is favored in some instances for its taste, high caffeine content, and ability to add body to espresso and espresso-based coffees; it is now the species of choice for instant coffee."

If we don't do something to protect wild coffee species, we might soon be drinking nothing but robusta coffee.

If that seems implausible, recall that this already happened to the banana. In the mid-1900s, the entire worldwide production of bananas was basically wiped out by Panama disease, caused by a fungus. Before then, a tasty variety called Gros Michel was the dominant species, but thanks to the fungus:

"By 1960, the Gros Michel was essentially extinct and the banana industry nearly bankrupt. It was saved at the last minute by the Cavendish, a Chinese variety that had been considered something close to junk." (Source: NYTimes)

Now, the robusta bean is far better than "junk," but I for one prefer my arabica coffee.

The main threats to arabica (and robusta) are outbreaks of mold and fungal infections, not unlike the disease that wiped out bananas. Those 122 wild species–of which 60% are now endangered–are often resistant, allowing plant scientists to inter-breed the wild and domesticated varieties to create new strains that resist disease and taste just as good as the original. This wild "reservoir" of coffee is critical to saving coffee as we know and love it today.

You're probably accustomed to seeing coffee labelled by the region it's grown in, rather than the type of bean. This is similar to how we label wines as being from France, California, Australia, etc. Coffee is grown in many temperate regions, including Central and South America, Indonesia, central Africa, and Hawaii. Just as with wine, the climate makes a difference, but the bean itself is an even bigger factor. Consider the difference between cabernet, pinot noir, or sauvignon grapes for wine–in the same way, arabica bean coffees tastes quite different from robusta coffee.

If we don't pay attention to the threat to coffee, we might all be drinking a less-tasty brew in the years to come.

(Aside: I've been working for several years on a project to sequence Coffea arabica, the tetraploid genome of arabica coffee, and our results will likely be published soon. We're hoping that the genome will assist coffee scientists who are trying to breed new, disease-resistant varieties.)

Coffee causes cancer. Coffee prevents cancer. Who to believe?

California might soon start requiring Starbucks to warn its customers that coffee causes cancer. Has  California gone nuts, or is there something to this?

A lawsuit filed in 2010 by a group called the Council for Education and Research on Toxics is in its final stages, and the judge might rule soon unless the plaintiffs settle the case. Several of the plaintiffs, including 7-Eleven, have already settled and agreed to post warnings in their stores.

The basis for the lawsuit is that brewing hot coffee produces acrylamide, which is on a list of substances that California claims cause cancer or reproductive toxicity. (It's a very long list.) Even though acrylamide has been on the list since 1990, it wasn't until 2002 that Swedish scientists discovered that acrylamide is present in many foods.

As the American Cancer Society explains,

"Acrylamide is found mainly in plant foods, such as potato products, grain products, or coffee. Foods such as French fries and potato chips seem to have the highest levels of acrylamide."

Uh oh. Coffee, french fries, and potato chips. Where's the joy in life without these?

But wait a second: how come people aren't keeling over with cancer left and right, especially in our coffee-loving, french-fry-loving society? (And what about the French?)

It turns out the evidence against acrylamide is pretty sketchy. If you give it to mice in the lab, at doses 1000 times greater than the amounts found in food, it does seem to increase their risk of cancer. But mice are not people, and 1000 times is a whole lot of acrylamide. The ACS concludes that

"it’s not yet clear if acrylamide affects cancer risk in people."

It's just as easy to find claims that coffee prevents cancer. A 2017 review found that one cup of coffee a day is associated with a slight reduction in the risk of liver cancer and endometrial cancer. A 2010 review of over 500 studies found the same reductions, but a slight increase in the risk of bladder cancer among heavy coffee drinkers. Another large review in 2017, by Robin Poole and colleagues in the UK, found not only a reduced risk of cancer, but a reduction in heart disease and overall mortality.

The Poole study concluded:

"Coffee consumption seems generally safe within usual levels of intake, with [the] largest risk reduction for various health outcomes at three to four cups a day, and more likely to benefit health than harm."

Coffee lovers, rejoice! But let's not kid ourselves: no one is drinking coffee for its health benefits, are they? The stuff just tastes good.

Finally, in answer to my own question at the top of this article: yes, California has gone a bit nuts. Or, as the nonprofit American Council on Science and Health put it:

"If coffee is deemed carcinogenic, then the State of California will be required to give up all pretense at common sense and sanity."

An afterthought: the lawsuit may be just about money. As Bloomberg News explained last October, in a story about the California coffee case: "Unfortunately, it is very easy for ‘bounty hunters’ to file Prop. 65 lawsuits against even small businesses and the cost of settlement and defense often exceeds other types of abusive litigation." The American Council on Science and Health was even more blunt, calling it an attempt to grab "a giant bag of money."

Let's hope the judge in the California case pays attention to the science. Meanwhile, the rest of us can focus on more important questions, such as: dark roast or light? French press or drip?

Have another cup o' joe, it's good for you

My favorite science studies are the ones that tell us that what we're already doing is good for us. This story fits the bill. In the American Journal of Epidemiology this month, Janet Hildebrand and colleagues reported on a large study looking at the effects of coffee on throat cancers.

Let's get right to the good news: drinking coffee seems to reduce your risk of death from oral or pharyngeal cancer by about 50%. Drinking more coffee is better than drinking less, and drinking caffeinated (normal) coffee is better than decaf.

I knew there was something wrong with decaf.

Now for some details. This study is part of an enormous project, the Cancer Prevention Study II, with over 1 million participants who've been followed for 30 years. The participants regularly fill out questionnaires answering a variety of questions, including how much coffee and tea they drink. After excluding people with missing information about coffee drinking and those who already had cancer in 1982, the researchers still had over 950,000 people. Coffee drinking was categorized based on daily consumption: less than a cup (or none), 1-2 cups, 3-4 cups, and more than 4 cups. They asked about decaf coffee and tea drinking as well.

A study like this is hard to do well, because there are so many confounding variables, especially smoking. Smokers have a dramatically higher risk of throat cancer, and smokers also drink a lot of coffee. Hildebrand and colleagues did a good job at separating out this effect, looking at the risk of cancer in nonsmokers separately and adjusting the statistics accordingly.

Perhaps the most encouraging finding is this: in people who have been nonsmokers for at least 20 years, 1-2 cups of coffee per day corresponds to a 32% decrease in the risk of death from throat cancer.  More than 2 cups per day corresponds to a 64% decrease. And among all participants (including former smokers), more than 4 cups a day seemed to provide the greatest benefit.

Decaf coffee also seems to reduce the risk of fatal throat cancer, though not quite as much. Tea drinkers, in contrast, don't seem to get any benefit, not for this type of cancer.

All this comes with some very big caveats.  First, despite the very large size of the study, the number of deaths oral or pharyngeal cancer was very small, only a few hundred. (Oral/pharyngeal cancer is very common worldwide, but less common in the U.S., where this study was conducted, with about 7850 deaths per year. This includes cancers of the tongue, mouth, and pharynx.)  So the absolute risk is very small.  Another big caveat is that this study only looked at cancer deaths - it did not measure the risk of getting cancer in the first place.

But skepticism aside, drinking coffee seems to reduce the risk of oral cancer.  This confirms my long-held view that the three major food groups - coffee, chocolate, and red wine - are all good for you.  So the next time you feel like a second cup, or a third: drink up!