The French press, or plunger pot, is valued by many coffee drinkers for delivering a beverage with a full body and robust flavor profile. This immersion technique involves steeping coarse coffee grounds directly in hot water before separating them with a metal mesh filter. However, this unique brewing style, which maximizes flavor extraction, has prompted questions about its effect on long-term health, particularly concerning the lack of a traditional paper filter.
The Primary Concern: Unfiltered Oils and Cholesterol
The main health consideration regarding French press coffee involves naturally occurring oily compounds known as diterpenes, primarily cafestol and kahweol. These substances are present in the coffee bean and are readily extracted into the hot water during the immersion brew. Since the French press uses a coarse metal screen, these oil-based compounds pass directly into the finished drink.
Scientific research has consistently linked the high consumption of unfiltered coffee, such as French press or boiled coffee, to elevated levels of Low-Density Lipoprotein (LDL) cholesterol in the bloodstream. High LDL levels can contribute to the accumulation of plaque in the arteries. Studies indicate that drinking five cups of French press coffee daily over four weeks can increase LDL cholesterol levels by approximately 6 to 8%.
The mechanism behind this effect is related to how diterpenes interact with the body’s cholesterol regulation systems. Cafestol, the more potent of the two diterpenes, can interfere with receptors that manage cholesterol metabolism. These compounds suppress the activity of the LDL receptor, reducing the liver’s ability to remove excess LDL cholesterol from circulation. This interference results in a sustained increase in circulating LDL cholesterol levels.
How French Press Differs From Other Brewing Methods
The difference in health impact is rooted entirely in the filtration mechanism used after the grounds are steeped. The French press employs a metal mesh screen attached to a plunger, which only mechanically separates the bulk of the grounds from the liquid. This metal filter allows fine coffee particles and lipid-rich coffee oils to easily pass through into the cup, contributing to the signature texture and mouthfeel of the brew.
In contrast, methods like automatic drip machines or pour-over cones rely on paper filters. Paper is highly porous and absorbent, effectively trapping the coffee’s oily fraction. Since diterpenes reside in these oils, the paper filter acts as a barrier, preventing them from entering the final beverage. Switching from a metal mesh filter to a paper filter can reduce the concentration of cafestol in the finished cup by over 90%.
This mechanical difference explains why paper-filtered coffee is consistently associated with a lower impact on cholesterol levels. The paper removes the oils and catches the microscopic sediment that carries much of the diterpene content. The French press retains these substances, classifying it alongside other unfiltered methods, such as Turkish and boiled coffee, in terms of diterpene concentration.
Ways to Minimize Health Risks
For individuals who appreciate the taste of French press coffee but are concerned about cholesterol, several simple adjustments can mitigate the potential health risks. The most straightforward strategy is moderation, particularly for those with pre-existing elevated cholesterol levels. Limiting consumption to one or two cups of French press coffee per day is a recommended way to reduce overall diterpene intake.
A highly effective method to maintain the French press brewing style while eliminating diterpenes is to introduce paper filtration after the fact. Once the coffee is brewed and the plunger is pressed, the liquid can be carefully poured through a separate paper filter, such as a pour-over cone or Chemex. This secondary filtration step will trap the majority of the remaining oily compounds and fine sediment, yielding a cleaner cup with significantly lower cafestol levels.
Another factor influencing diterpene content is the degree of bean roasting. Darker roasts generally contain slightly lower amounts of cafestol and kahweol compared to lighter roasts. The prolonged exposure to high heat during the dark roasting process naturally breaks down some of these compounds, offering a marginal advantage for French press users.