Coffee is a perpetual topic of interest, and for good reason: Almost everyone drinks it, almost everyone is passionate about it, and it’s packed with compounds that are pretty darn good for you. One aspect of coffee I’ve never explored, however, is how coffee brewing methods affect its health effects.
What’s healthier—filtered or unfiltered? Dark roast or light roast? Pre-ground or whole bean? French press or drip? Let’s get to it.
Filtered coffee is coffee that runs through a paper filter, which catches most of the oils. Unfiltered coffee is coffee that doesn’t go through a paper filter; either it’s completely unfiltered (grounds directly in water) or it runs through a metal filter, which allows the oils to pass through. Unfiltered coffee is often referred to in the scientific literature as “boiled coffee.”
Filtered coffee includes drip, pour-over (unless you use a permanent filter that allows passage of the oils), and any method in which the coffee passes through a paper filter.
Unfiltered/boiled coffee brewing methods include French press, Moka pot/percolator, Aeropress, espresso.
Cold brew coffee can be either filtered or unfiltered, depending on what kind of filter you use to strain the final product.
Conventional wisdom is scared of those oils because they contain two lipid compounds called cafestol (great name for a coffee shop) and kahweol, high doses of which elevate cholesterol and suppress LDL clearance from animal models. That does sound bad; suppressed LDL clearance means LDL particles hang around longer in the blood to be oxidized and form atherosclerotic lesions. Do the animal mdoels transfer over to humans?
Maybe not. While 73 mg of purified cafestol a day for six weeks can increase cholesterol by a worrisome 66 mg/dL, the average cup of French press coffee contains between 3-6 mg; 73 mg isn’t a normal physiological dose. In one study, boiled coffee consumption was associated with a more modest 8% cholesterol increase in men and a 10% increase in women. That’s cholesterol, not LDL. Total. Besides, high fitness levels abolished the link in men, and boiled coffee was also linked to lower triglycerides in both sexes.
Or maybe. Another study found a modest association between high intakes of boiled coffee and non-fatal heart attacks. Then again, a similar (but smaller) association also existed with filtered coffee. Tough to say.
Cafestol and kahweol have beneficial effects, too. For instance, cafestol kills leukemia cells and kidney cancer cells. In mice, cafestol exerts anti-diabetic effects. Kahweol inhibits fat accumulation by activating AMPK (the same pathway triggered by fasting, exercise, and ketosis). Both compounds have anti-angiogenic effects.
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Both boiled and filtered coffee reduce the risk of type 2 diabetes, but only boiled coffee confers a lower risk of prostate cancer. Liver enzyme levels drop when you consume boiled coffee, and when you inject rats with a known liver toxin, boiled coffee protects them against the expected rise in liver enzymes. Most evidence suggests that coffee, whether boiled or filtered, is protective against liver cancer, liver disease, and mortality from chronic liver disease.
If you want the unfiltered coffee with the most cafestol and kahwehol, brew a light roast using a French press or the boiling method. If you want the unfiltered coffee with the least cafestol and kahwehol, brew a dark roast using a Moka pot or use the Turkish method. If you want the least of all, use a paper filter.
If you’re a heavy consumer of unfiltered coffee and you worry about the cholesterol issue, get it tested. Go for a full lipid panel, one that includes LDL particle number.
What about the specific methods of brewing? How do they stack up against each other?
Espresso machines use hot water and high levels of pressure to extract the essence of the coffee bean and deliver a concentrated dose. Bad espresso made with bad beans is awful. Bad espresso made with good beans is pretty bad, too. But good espresso made with good beans? Incredible.
Espresso shots actually have less caffeine than a cup of brewed coffee made with the same beans. However, because espresso shots are so concentrated, there is more caffeine-per-ounce of espresso.
Espresso machines contain no plastic, so there’s no danger of plastic compounds ending up in your cup.
Espresso shots are considered unfiltered, meaning they contain the cafestol and kahwehol.
My tip: Let the espresso linger in your mouth, not only to savor the flavor but to also take advantage of sublingual caffeine absorption.
Drip coffee machines line nearly every kitchen counter in the United States. They’re what most people imagine when they think “coffee maker.”
Drip coffee has some of highest caffeine content.
Most drip machines have tons of plastic. That may or may not be a problem, but if you’re worried about the effect of plastic compounds on health, you might not want to drink a few cups of near-boiling water that have been circulating through plastic.
Drip coffee is usually filtered through paper, removing the oils, although you can buy filters for drip coffee machines that allow the oils passage into the cup.
Turkish coffee is made by grinding beans to a very fine powder and mixing it directly into a pot of water, bringing it to a boil, and then letting it sit for a few minutes. You do not filter the grounds. You let them settle to the bottom. I’ve made this while camping—cowboy coffee. Traditionally, Turkish coffee is brewed with ample amounts of sugar in a copper pot. I don’t recommend any more than a teaspoon, just to cut down the bitterness.
Turkish coffee is very strong with a high caffeine content.
Turkish coffee is plastic-free.
Turkish coffee is totally unfiltered.
These are the “pod” coffees. Proprietary single serving pods of pre-ground coffee that fit into machines made specifically for those pods. Keep the carafe filled with water, place the cup in the right spot, press a button or two, and in a few minutes you have a single serving of coffee. Keurig is the most well-known brand of single serving pod coffees.
The caffeine content will be fairly standard because the pods are so homogeneous. If you want s more concentrated (stronger) cup, select the option that uses less water.
Pod coffee is filtered.
I’m still a little nervous about drinking coffee from a plastic pod. It doesn’t feel right. I’ll drink it when that’s what the hotel room is offering, however.
The French press is a simple way of making coffee. It’s a carafe with a filter attacked to a plunger. Fill the carafe with grounds, add hot water, stir, let set for a few minutes, then plunge the filter down. My preferred method is the French press. See below for exactly how I do it.
French press coffee will be as strong as you make it.
There are plastic-free stainless steel French presses. Many of the glass presses have plastic components, although they typically only have brief interactions with the water.
French press coffee is usually unfiltered but there are paper filters that fit the carafes.
I love cold brew, especially in the spring and summer. It’s made by soaking grounds with water at either room temperature or in the fridge, then straining them out to form a cold brew concentrate which you can then drink straight or cut with milk, cream, or more water.
Cold brew tends to be high in caffeine because of the long soaking time and the concentrated ratios (oftentimes 1:4 coffee to water). If you dilute that concentrate with a bunch of milk or water, the caffeine concentration drops. There’s nothing inherent to the cold brew process that extracts more caffeine from the bean.
Cold brew coffee can be filtered or unfiltered. It’s all in how you filter out the grounds and whether you pour the finished product through a paper filter.
Low pressure espresso. A moka pot has two chambers. One on the bottom for the water, one above it for the finished coffee. Over a low heat, the pressure from the steam builds, forcing water up through the grounds into the top chamber to produce a concentrated “light” espresso.
Moderate caffeine content. It can be very concentrated, depending on how much coffee you add.
Moka pots are plastic free but they are traditionally made of aluminum, a metal with problematic health associations. If you’d prefer stainless steel (I would), you can find that too.
Moka pot coffee is unfiltered.
Coffee beans start out green and fairly uninteresting. It’s the roasting that brings out the flavors. The darker the roast, the longer it spends in the roaster.
Light roast advantages include less oil oxidation. The lighter the roast and the fresher the coffee, the lower the oil oxidation. Keeping it in whole bean form also increases the resistance, while grinding it prematurely will oxidize the oil and mar the taste.
Light roasts tend to have more caffeine, as the roasting process degrades caffeine. But caffeine content also depends on the bean; some have more than others.
Both are good, health-wise. Some studies suggest that dark roast has a better effect than light roast on antioxidant capacity in those who drink it. Light roasts tend to be higher in chlorogenic acids, which have been shown to improve subjective mood and ability to focus—even when the coffee is decaf. Medium roasts also have antioxidant effects.
They’re all good. Coffee just works.
Depends. I like whole bean, because keeping it intact until you’re ready to brew increases the oxidative resistance (more surface area means more oxidation). It retains the aroma and flavor, and—this is seemingly minor but still important to me—I like the sound of grinding beans. The sound is a huge part of the ritual of coffee preparation. It’s the same reason instant coffee just isn’t the same as whole bean coffee. It’s almost too easy.
Healthwise, I imagine pre-ground beans are fine. Despite a huge number of people buying and drinking pre-ground coffee, coffee is consistently associated with health benefits in observational studies. If you believe the observational studies are pointing toward causality, ground coffee is good for you. And if you have the opposite relationship to grinding beans, and having whole coffee beans makes it less likely that you’ll drink coffee, go with the ground. It’s fine.
The quality of the water matters. Mineral content is the primary concern. A 2014 study sought to determine the optimal “hardness” for coffee water and found that the specific minerals causing the hardness made a big difference.1
You don’t want too much bicarbonate. Bicarbonate is bad for coffee flavor.
Sodium was also bad for coffee flavor.
You want some magnesium. Magnesium is good for coffee flavor because it enhances the dissolution of coffee flavor from beans into the water. Since coffee flavor comes from the coffee compounds, and the coffee compounds are responsible for many of the beneficial health effects, better coffee is also probably healthier coffee.
I find adding a few dashes of Trace Minerals to my coffee brewing water helps the flavor.
When you include coffee:water ratios, water quality, brew method, filter choice, ground size, and all the other variables, there are millions of ways to make coffee. I won’t get into all of them. I’m actually not a big coffee snob, although I do know a good cup when I taste it. I’ll just give my basic method.
Sometimes I make cold brew coffee concentrate:
That’s it for today, folks. I think I’ll go make another cup.
How do you make coffee? Tell me all about it down below.
References
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