Cold brew coffee is made by steeping coarse coffee grounds in cold or room-temperature water for an extended period, often 12 to 24 hours. This process yields a coffee concentrate known for its smooth taste and low acidity, making it a popular choice for those with sensitive stomachs or a preference for iced beverages. The primary concern for a pregnant individual considering this drink is the highly variable and often extreme concentration of caffeine.
Caffeine Content and Pregnancy Safety Limits
Health organizations, such as the American College of Obstetricians and Gynecologists, advise pregnant individuals to limit their total daily caffeine intake to 200 milligrams or less. This limit is set because caffeine is a stimulant and a diuretic that readily crosses the placenta. The developing fetus lacks the mature metabolic enzymes needed to process and eliminate the compound efficiently, leading to prolonged exposure. Regularly exceeding the 200 milligram threshold may increase the risk of pregnancy complications, including fetal growth restriction and low birth weight.
Cold brew is uniquely problematic because it is typically prepared as a concentrate using a high coffee-to-water ratio and a long extraction time. This results in a much higher concentration of caffeine per fluid ounce than standard drip coffee. While a standard 8-ounce cup of hot brewed coffee contains 70 to 140 milligrams of caffeine, a 12-ounce serving of ready-to-drink cold brew can easily contain 150 to 240 milligrams, depending on the brand and preparation. Just one medium-sized, undiluted serving can meet or even exceed the daily recommended limit.
Consumption of caffeine above the recommended limit has been associated with an increased risk of miscarriage. Caffeine can cause blood vessels in the placenta to constrict, which may reduce blood flow and inhibit fetal growth. Given the wide range of caffeine content in cold brew products, drinking without dilution or precise measurement makes it difficult to stay within safety guidelines.
Non-Caffeine Safety Concerns
Beyond the stimulant content, the unique preparation method of cold brew introduces distinct microbial safety considerations that differ from hot-brewed coffee. Unlike traditional brewing, which uses boiling water to sanitize the grounds and equipment, cold brewing relies on low temperatures that do not kill potential pathogens. This creates an environment where certain bacteria can survive and thrive.
The lower acidity of cold brew (pH 4.85 to 5.6) is less inhibitory to bacterial growth than the highly acidic environment of hot coffee. If the brewing container or water is not sanitary, or if the concentrate is stored improperly, this can allow for the survival of foodborne pathogens like E. coli, Salmonella, and Bacillus cereus. Studies show that Bacillus cereus, a spore-forming bacterium, can persist in cold brew even when stored under refrigeration past 21 days.
Mold can grow on coffee beans during harvesting and storage, producing toxic compounds known as mycotoxins. While quality control in commercial production aims to keep these levels low, pregnant individuals may wish to minimize exposure by choosing high-quality, reputable brands. The advantage of cold brew’s low acidity is that it is often better tolerated by individuals experiencing pregnancy-related heartburn or gastroesophageal reflux disease (GERD). The cold water extraction process pulls out up to 60 to 70 percent fewer acidic compounds that often trigger digestive discomfort.
Managing Cold Brew Intake
For pregnant individuals who choose to consume cold brew, careful management and precise measurement are required to ensure intake remains below the 200-milligram limit. Since cold brew is almost always a concentrate, dilution is mandatory before drinking to achieve a safe strength. A common starting point for dilution is a 1:1 ratio of concentrate to water or milk, though a 1:2 ratio may be necessary for a milder beverage.
The strength of commercial concentrates varies widely, making it difficult to rely on simple serving size estimates. Individuals must check the label for the specific caffeine content per fluid ounce of the concentrate. Alternatively, they should assume a high concentration and measure the volume precisely using a measuring cup. The final drink should aim for a brewing strength equivalent to a standard cup of coffee, which falls within a 1:15 to 1:18 coffee-to-water ratio.
To reduce overall caffeine intake while still enjoying the flavor, pregnant individuals can switch to decaffeinated cold brew or blend regular concentrate with a decaffeinated version. Diluting the concentrate with milk or a milk alternative can naturally reduce the strength and provide some nutritional benefit. When making cold brew at home, all equipment should be sanitized. The concentrate must be brewed and stored in the refrigerator to minimize microbial risk.