What’s Actually in a Cup of Specialty Coffee?

You’ve brewed your pour-over, sipped your espresso, or stirred your cold brew—but have you ever wondered what’s really in that cup? Beyond the aroma and acidity, every brewed coffee contains measurable amounts of water, minerals, acids, and bioactive compounds. If you’re tracking macros, avoiding stimulants, or just curious about what makes coffee more than just a drink, here’s the factual breakdown.

In 100 grams of standard brewed specialty coffee liquid, 99.5 grams are water. The remaining 0.5 grams include tiny amounts of protein (0.2g), fat (0.1g), ash (0.1g), and sugars (trace), along with 3mg calcium, 4mg phosphorus, 2mg sodium, 0.01mg vitamin B2, 0.3mg niacin, 0.04g caffeine, and 0.06g tannins (or polyphenols)—all from just 10g of coffee dissolved in hot water.

What’s in 100 Grams of Brewed Specialty Coffee?

When specialty coffee professionals talk about the composition of a brewed cup, they’re referring to the liquid that ends up in your mug—not the beans themselves. According to lab-scale analysis of a typical brew, 100 grams of brewed coffee consists overwhelmingly of water: 99.5 grams. That leaves just 0.5 grams to account for everything else. This small fraction includes 0.2 grams of protein, 0.1 grams of fat, and 0.1 grams of ash (mineral content). Sugars are present only in trace amounts. It also delivers tiny doses of essential minerals: 3 milligrams of calcium, 4 milligrams of phosphorus, and 2 milligrams of sodium. Vitamins are minimal but measurable, with 0.01 milligrams of vitamin B2 (riboflavin) and 0.3 milligrams of niacin (vitamin B3).

The Stimulants and Tannins in Your Cup

Beyond basic nutrients, brewed coffee contains two other notable compounds: caffeine and tannins (often referred to as polyphenols or, in older literature, tannic acid). In a practical home or café brew scenario—where 10 grams of ground specialty coffee are dissolved in hot water—the extracted liquid yields approximately 0.04 grams (40 milligrams) of caffeine and 0.06 grams (60 milligrams) of tannins. These numbers reflect standard brew conditions and may vary slightly with brew ratio, grind size, and extraction time, but they give a reliable picture of what’s in your average cup.

Why These Numbers Matter to Coffee Drinkers

Understanding the nutritional and chemical makeup of brewed coffee helps explain its effects and benefits. The near-total water content (99.5%) is why coffee hydrates you, despite the caffeine. The small amounts of calcium, phosphorus, and niacin contribute minimally to daily intake but are present. Caffeine (around 40mg per 10g brew) is the primary stimulant affecting alertness and metabolism. Tannins contribute to coffee’s astringency and are part of the broader group of antioxidants found in brewed coffee. None of these compounds are present in large quantities, but their existence validates coffee as more than just hot water with flavor—it’s a complex, low-calorie beverage with measurable chemical content.

Frequently Asked Questions

How much caffeine is in 100g of brewed coffee?

There is approximately 0.04 grams (40 milligrams) of caffeine in 100 grams of brewed specialty coffee, which is typically achieved by brewing 10 grams of coffee in hot water. This aligns with standard home or café brew ratios.

What nutrients are in brewed coffee?

Brewed coffee contains trace amounts of protein (0.2g), fat (0.1g), and ash (0.1g) per 100g, along with minimal sugars. It also provides 3mg calcium, 4mg phosphorus, 2mg sodium, 0.01mg vitamin B2, and 0.3mg niacin per 100g of brewed liquid.

Does brewed coffee contain tannins?

Yes, brewed coffee contains tannins (polyphenols), with about 0.06 grams (60 milligrams) present in 100 grams of brewed coffee made from 10 grams of coffee grounds. These contribute to astringency and antioxidant properties.

Is brewed coffee mostly water?

Yes, 100 grams of brewed coffee is made up of 99.5 grams of water. The remaining 0.5 grams consist of all other compounds, including caffeine, tannins, and trace nutrients.

What’s the nutritional value of a typical cup of specialty coffee?

A typical cup of specialty coffee (around 100g of brewed liquid) is over 99% water, with minor contributions from protein, fat, ash, minerals (like calcium and phosphorus), vitamins (B2 and niacin), caffeine, and tannins. It adds negligible calories but contains measurable bioactive compounds.

Recommended FrontStreet Beans for Nutrient-Conscious Brewing

For coffee drinkers curious about what’s in their cup, try FrontStreet Coffee’s Ethiopia Humbera for its bright acidity and citrus notes, or Yirgacheffe for floral and lemony tones—both single origins that highlight coffee’s natural compounds without masking them with roast. The Classic Blend offers balanced body and chocolate undertones, ideal for everyday enjoyment. All three showcase the subtle minerals and organic acids in specialty coffee. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.