How to choose and brew coffee: paper filters and decaf
3 min read
In "Is coffee really bad for you?" I went through why usual amounts of coffee are considered generally safe.
QUIZWith coffee, what changes the effect on your body the most? A. Where the beans are from B. How dark the roast is C. How it's brewedShow answer
C. How it's brewed.
The oily compounds that raise LDL cholesterol are mostly removed by a paper filter. Studies found a difference compared with brewing methods that don't use one.
So what coffee should you drink, and how should you brew it? Looking into it, what turned out to matter surprisingly much was the brewing method.
Contents
Paper filters reduce coffee oils
Coffee beans contain oily compounds (diterpenes) called cafestol and kahweol. These are known to raise LDL cholesterol in the blood.
A meta-analysis of randomized controlled trials on coffee and cholesterol found that the tendency for coffee to raise cholesterol was large with unfiltered coffee, such as boiled coffee, and barely seen with coffee brewed through paper filters [1]. The paper filter is thought to catch these oily compounds.
- Examples of unfiltered brewing: boiling in a pot, French press
- Brewing with a paper filter: pour-over (paper drip)
The brewing difference showed up in a long follow-up study too
A study in Norway that followed more than 500,000 people for an average of 20 years found that, compared with people who didn't drink coffee, people who drank filtered coffee had a lower risk of death. For people who drank unfiltered coffee, that relationship was weaker. The lowest risk of death was among people drinking 1–4 cups of filtered coffee a day [2].
This is an observational study too, so we can't say the brewing method alone is the cause. Still, it points in the same direction as the cholesterol experiments.
POINT
If you're thinking about your body, brew your coffee through a paper filter.
To cut caffeine, decaf
When you want a cup at night, or need to limit caffeine during pregnancy or breastfeeding, there's "decaf" or "caffeine-free" coffee with the caffeine removed.
But the caffeine doesn't go to zero. How much must be removed to be labeled decaf differs by country. In Japan, where I live, the industry standard is that "caffeine-less coffee" has had 90% or more of its caffeine removed [3]. Drink a lot, and you take in caffeine accordingly.
For sweetened coffee drinks, read the label
Many canned and bottled coffee drinks contain sugar or dairy. The results of research on coffee itself don't apply as-is to drinks loaded with sugar.
When buying, check the carbohydrate (sugar) amount on the nutrition label, and whether sugar is first in the ingredients list. If you drink it every day, choosing unsweetened is the safer choice, also with blood sugar in mind.
Summary
| What to look at | What to choose |
|---|---|
| Brewing | Brew through a paper filter (pour-over) |
| Caffeine | Decaf at night or when cutting back. It isn't zero, so mind the amount |
| Ready-made drinks | Unsweetened if it's daily. Check the sugar on the label |
| Amount and timing | The guidelines in the original article (up to 400 mg a day, go easy late in the afternoon) |
If you choose by these guidelines
References
1. Jee SH, He J, Appel LJ, Whelton PK, Suh I, Klag MJ. (2001). Coffee consumption and serum lipids: a meta-analysis of randomized controlled clinical trials. American Journal of Epidemiology, 153(4), 353–362.
2. Tverdal A, Selmer R, Cohen JM, Thelle DS. (2020). Coffee consumption and mortality from cardiovascular diseases and total mortality: Does the brewing method matter? European Journal of Preventive Cardiology, 27(18), 1986–1993.
3. All Japan Coffee Fair Trade Council. Fair Competition Code concerning the labeling of regular coffee and instant coffee (in Japanese).