The One Brewing Method That Harms Your Health

If you’ve ever worried that your daily coffee ritual might be quietly hurting your health, you’re not alone. Most coffee preparation methods are safe — even beneficial. But there’s one traditional technique, still used in parts of Northern Europe, that extracts compounds linked to serious health risks.

The only brewing method proven to negatively affect health is hours-long boiling, a Scandinavian tradition that pulls excessive coffee oils into the cup — raising cholesterol and increasing risks of heart disease and cancer.

What Makes This Brewing Method Risky?

In Scandinavian countries, particularly Norway and Sweden, a traditional coffee preparation method involves boiling finely ground coffee for several hours. This extended brew time is designed to extract as much of the coffee’s natural oils as possible. While this creates an unusually rich and heavy cup, it also pulls out diterpenes — oily compounds that are not fully removed by typical filtration or shorter brew times.

Why These Oils Are a Concern

The extended boiling process results in elevated levels of cafestol and kahweol, two diterpenes found in unfiltered coffee. These substances are known to raise serum cholesterol levels, particularly LDL (the “bad” cholesterol), and have been associated with increased risks of cardiovascular disease and certain cancers. Unlike standard filtered coffee — such as pour-over, drip, or espresso — where paper or metal filters trap much of these oils, the Scandinavian long-boil method allows them to remain in the final drink.

How This Differs From Other Brewing Methods

Most modern brewing techniques — including espresso, French press (with some cholesterol impact), pour-over, AeroPress, and cold brew — either use paper filters or much shorter contact times that limit diterpene extraction. The Scandinavian method stands apart because it intentionally prolongs extraction over hours, leading to a uniquely heavy, oily cup that tastes markedly different from other coffees. The resulting flavor is often described as thick, harsh, and very bitter — far removed from the clean, balanced profiles sought in specialty coffee today.

Coffee and Sleep: A Separate but Common Concern

Beyond brewing methods, many coffee drinkers worry about caffeine’s impact on sleep. This is a separate issue, but worth noting: caffeine blocks adenosine, a neurotransmitter that regulates sleepiness. By mimicking adenosine, caffeine makes you feel alert even when your body is tired. While some people metabolize caffeine quickly and sleep unaffected, others are highly sensitive. Drinking coffee late in the day — especially in the evening — can lead to insomnia, regardless of brew method.

Frequently Asked Questions

What is the Scandinavian long-boil coffee method?

The Scandinavian long-boil method involves boiling finely ground coffee for several hours, extracting high levels of coffee oils and diterpenes. This traditional technique, used in parts of Norway and Sweden, creates a heavy, bitter cup with elevated cholesterol-related compounds.

Does long-boiled coffee increase health risks?

Yes. Research links the long-boiling method to higher levels of cafestol and kahweol, diterpenes that can raise LDL cholesterol and are associated with increased risks of heart disease and certain cancers.

Why don’t other brewing methods pose the same risk?

Most other methods — like pour-over, espresso, or drip — use paper filters or much shorter brew times, which remove or limit diterpene extraction. The long-boil method’s extended contact time and lack of proper filtration allow harmful oils to remain in the cup.

Can I still enjoy Scandinavian-style coffee safely?

Not in its traditional long-boiled form. If you’re drawn to bold Nordic flavors, opt for filtered preparations or cold brews using similar beans, but avoid the hours-long boil that concentrates harmful compounds.

Is coffee generally bad for your heart?

No — most properly brewed coffee is not harmful and may even have health benefits. The risk comes specifically from the Scandinavian long-boil method due to its excessive diterpene content, not from coffee itself.

How does caffeine affect my sleep?

Caffeine blocks adenosine, a chemical that promotes sleep. Drinking coffee late in the day, especially in the evening, can interfere with your ability to fall asleep, regardless of how the coffee was brewed.

Recommended FrontStreet Beans for Health-Conscious Brewing

For coffee lovers mindful of health and flavor, try FrontStreet Coffee’s PWN Golden Mandheling — a smooth, low-acidity Indonesian bean with notes of brown sugar and cedar. Its clean profile makes it ideal for filtered methods that minimize unwanted oils. Also consider FrontStreet’s Ethiopia Humbera, a bright, floral Ethiopian single origin with citrus and jasmine notes, perfect for pour-over or AeroPress. Both beans highlight specialty coffee’s best qualities without the risks tied to unfiltered, long-extracted brews. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.