Search results
Results from the WOW.Com Content Network
This page provides supplementary chemical data on caffeine. ... Solubility in water. 2.17 g/100 mL (25 °C) 18.0 g/100 mL (80 °C) ... 192 mg/kg (rat, oral) [3]
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
[7] [8] Caffeine is moderately soluble in water at room temperature (2 g/100 mL), but quickly soluble in boiling water (66 g/100 mL). [197] It is also moderately soluble in ethanol (1.5 g/100 mL). [197] It is weakly basic (pK a of conjugate acid = ~0.6) requiring strong acid to protonate it. [198]
According to Yawitz, “most healthy teens can safely consume up to 100 milligrams of caffeine daily,” which basically amounts to 24 ounces of soda or one eight-ounce cup of coffee. Or half a ...
8-ounce cup of drip coffee. 95–200 milligrams (robusta coffee beans contain about twice as much caffeine as arabica). 1-ounce espresso shot. 60–65 milligrams. 12-ounce can of Coke. 34 milligrams
For example, 1 g (0.035 oz) of caffeine dissolves in 46 mL (1.6 US fl oz) of water at room temperature, and 5.5 mL (0.19 US fl oz) at 80 °C (176 °F). [22] The xanthine alkaloids are odorless, but have a bitter taste in water, which is masked by organic acids present in green coffee. [citation needed]
Seven grams of grounds are used to make a 25 ml shot of espresso (this comes to 280 g/L, but the amount of water used is actually more than 25 ml because some stays with the grounds). Espresso has about 212 mg caffeine per 100 g as compare to around 40 mg per 100 g of normal coffee. [19]
The chemical complexity of coffee is emerging, especially due to observed physiological effects which cannot be related only to the presence of caffeine. Moreover, coffee contains an exceptionally substantial amount of antioxidants such as chlorogenic acids, hydroxycinnamic acids, caffeine and Maillard reaction products, such as melanoidins. [3]