Each bean contains 0.8 - 2.5 % caffeine. For your information in an average cup of coffee you have 75mg caffeine. One cup of coffee contains around 25 coffee beans, and you are not getting the full coffee bean in coffee, so the caffeine can add up if you eat a lot.
The reason why temperature effects muscles is because of the numerous atoms in the body that react to temperature. When the air, or body temperature is colder the atoms tend to stay closer together, causing less movement...when it is hot, the atoms (molecules) move around more, causing more range of motion. It also allows blood to flow more easily when it is warm than cold.
Exercise and work performance, as well as acclimatization to cold (see below), depend on more than the temperature of the air or water surrounding the body. If several layers of insulative clothing are worn, for example, it is possible that core body temperature might even rise during exercise in the cold. Therefore, regardless of the severity of cold exposure, you should focus on the effects on physical performance of a fall in core temperature or muscle temperature. Cardiorespiratory endurance will likely decrease if the whole body cools, and this is more likely to occur if exercise in cold air is prolonged.