Cold brew coffee, made by steeping coarse coffee grounds in cold water for an extended period, has become a popular alternative to traditionally brewed hot coffee. This method yields a smoother, less bitter beverage, but like all coffee, it is strongly associated with digestive stimulation. Determining whether cold brew specifically makes you “go” involves understanding the science behind coffee’s effect on the gastrointestinal tract and how the cold brewing process alters its chemical composition.
The Direct Answer: Caffeine and Bowel Motility
The primary mechanism behind coffee’s effect on bowel movements is the action of caffeine. Caffeine is a powerful central nervous system stimulant that also directly affects the muscles of the digestive system. In the colon, caffeine significantly increases motor activity, causing the muscles to contract more vigorously than they would otherwise.
This stimulated movement is known as peristalsis, the wave-like muscle contraction that pushes waste through the large intestine toward the rectum. Research suggests that caffeinated coffee can make the colon about 60% more active than water and 23% more active than decaffeinated coffee. This effect can begin rapidly, with some studies noting an increase in rectosigmoid motility within four minutes of consumption. Approximately one-third of people report an urge to defecate shortly after drinking coffee.
Beyond Caffeine: Other Stimulants in Coffee
The digestive response to coffee is not solely dependent on caffeine; other bioactive compounds contribute to its motility-promoting effects. Decaffeinated coffee also stimulates the colon, indicating that non-caffeine components play a significant role by triggering the release of digestive hormones.
Coffee contains acids that boost the levels of the hormone gastrin, which stimulates involuntary muscle contractions in the stomach and colon. The release of cholecystokinin (CCK), another hormone involved in digestion, is also stimulated by coffee consumption. These hormonal signals speed up the transit time of contents through the gut.
Polyphenols, such as chlorogenic acids (CGAs), and compounds created during roasting, like melanoidins, also influence the gut. CGAs are largely unabsorbed and reach the colon, where they interact with the gut microbiota to produce metabolites that affect motility. Melanoidins, formed when sugars and amino acids react under heat, contribute to the coffee’s antioxidant properties and may promote colon function.
The Cold Brew Factor: Acidity and Concentration
The defining characteristic of cold brew is its preparation method: steeping grounds in cold water for 12 to 24 hours. This process results in a distinct chemical profile compared to hot-brewed coffee, extracting significantly fewer acidic compounds, such as quinic and chlorogenic acids.
Traditional hot coffee typically has a pH around 4.8 to 5.0, while cold brew often registers a higher pH, closer to 5.5 or even higher, making it up to 60-70% less acidic. For individuals with sensitive stomachs or acid reflux, this lower acidity can reduce stomach irritation and the potential for discomfort. The cold brew method may therefore be gentler on the digestive tract.
However, cold brew is typically prepared as a concentrated extract that is diluted before drinking. This concentration often means a standard serving may contain a higher total amount of caffeine than a typical cup of hot coffee. A higher caffeine dose results in a more pronounced stimulation of colonic motor activity, potentially counteracting the milder effects of the lower acidity. The overall effect on bowel movements is a balance between its lower acidity and its often higher concentration of stimulating compounds.
Consumption Style and Secondary Effects
The way a person consumes cold brew can introduce secondary factors that contribute to, or even overshadow, the coffee’s inherent laxative effect. Many popular cold brew preparations include the addition of dairy products.
An estimated 65% of people worldwide have difficulty digesting lactose, the sugar found in milk and cream. For those who are lactose intolerant, consuming dairy additives with cold brew can cause symptoms like bloating, gas, and diarrhea, which are often mistakenly attributed solely to the coffee.
Furthermore, many cold brew beverages are heavily sweetened with syrups or sugars. High sugar intake creates an osmotic effect in the intestines, drawing water into the digestive tract and potentially leading to looser stools or diarrhea. Consuming a large volume of any liquid, including cold brew, also contributes to gastrocolic reflex activation and increased motility by stretching the stomach.