There are two types of coffee bean, arabica and robusta. The arabica is meant to be smoother and more flavoursome. It is generally more expensive than robusta, with spot prices of roughly $2.50 per pound against robustas $1.10. These prices have dropped recently, but with a coffee shortage predicted by Starbucks chief sustainability officer this October the price of coffee long term is probably set to rise significantly.
Coffee is grown on trees and appears as cherry like fruits. These are picked when they are red and each contain 2 sticky seeds which are the recognizable to us as green coffee beans. The robusta variety is more bitter and generally contains more caffeine. The robusta plant is also more resilient to disease. Most coffee is grown in Brazil with the 2nd biggest producer being Vietnam a fact that will surprise many people. It surprised me.
Coffee and the environment.
The coffee shrubs can be grown in the shade of trees which would naturally occur in their environment or in open sun with fertilizer. The shaded method is far more friendly for the environment as it avoids the deforestation and soil erosion inherent in the sun grown method. However yields are less with the shade grown shrubs as more fertilizer can be used with coffee shrubs grown in the open sun.
The cherries are processed by either a wet or dry method. The dry or natural method involves drying the cherries and when they are dried they are then processed to remove the fruit pulp and other layers. The dry method is used for virtually all types of robusta bean and a number of the arabica beans. It is the oldest and most environmentally friendly method. The wet or washed method involves soaking the beans in water and then either fermenting them to remove the sticky outer layer or processing them by a machine for the same purpose. The beans are then washed and dried. The wet method involves washing the beans in copious amounts of water, which has been estimated at 147 litres for one cup of coffee. The water often gets contaminated with strong chemicals used to wash the beans and from the beans themselves. In countries where environmental controls are poor this can lead to significant pollution of waterways.
Decaffeination of coffee, by using an extra processing step is less environmentally friendly than caffeinated coffee. It involves mixing green beans with solvent or high pressure carbon dioxide prior to roasting them. Inevitably there is usage of energy and the creation of more pollution in this process.
Coffee and the health.
The beans are then roasted which is when they become recognizable as the brown beans we see in our coffee shops. Roasting at 200C changes the starches in each bean into sugars. The content of oils in the bean also changes so that some oils decrease while others increase. One of the oils that increases is caffeol, which is responsible for much of the coffee aroma. Generally speaking darker roasts contain less fibre and are more sugary while lighter roasts are said to have more flavour.
Coffee contains caffeine, a substance very similar to theophyline in tea and cocoa and theobromine in cocoa. Interestingly it is also very like a chemical we all use to make our DNA, xanthine. The fact that it contains 3 more methyl groups (CH3) than xanthine gives it potential as a powerful health booster, as methyl groups are responsible for reducing cancer risk and other damamging changes in the body.
Studies have shown a link between coffee drinking and reduced risk of brain diseases, in particular Parkinson's, but also Alzheimer's and vascular dementia1. It is also associated with reduced risk of heart disease2 and diabetes3.
While the caffeine in coffee can raise blood pressure it has been found that regular drinkers become habituated to caffeine and have a reduced blood pressure response to it. Coffee also contains substances such as chlorogenic acid, trigonelline and magnesium which help relax blood vessels and inflammation, both effects that explain why studies show no increased risk of heart disease for coffee drinkers.
Some people are sensitive to the effects of coffee, in particular overconsumption can cause heart palpitations in some people. It can also make some people anxious and unable to relax. If either of the aforementioned apply to you then it is probably best to cut down on coffee or switch to a decaffeinated brand which will still confer some of the benefits of regular coffee.
If you want to get the maximum benefit from home drunk coffee my view is that you should grind the beans yourself. This imparts a fresher flavour and is likely to leave in more of the healthy substances. It really does taste an awful lot better than instant coffee. When it comes to coffee shops then I suggest that small speciality shops are often the best. The big chains produce coffee of varying quality with Cafe Nero and Costa coffee being OK. Starbucks is lower down the order. Needless to say, if you add milk, cream and sugar to your coffee the health benefits are modified, normally for the worse.
How much coffee should you drink? Well that is probably an individual thing, but if you are drinking more than 4-5 cups a day you are probably becoming partially dependent on the caffeine which is not a good thing. Above this level many people will experience palpitations, altered mental states and dependency. If you don't have any negative reactions and you enjoy coffee then DrDobbin's advice is to drink 1-4 cups a day, ideally of fresh ground black coffee! It will very likely be beneficial for your long term health.
Coffee and the athletic performance.
The caffeine in coffee leads to improved athletic performance for some people. This is due to its ability to decrease our perception of effort so we can push harder during races. It is also likely that it could improve fat-burning ability, as caffeine stimulates the release of free fatty acids from fat tissues, allowing our muscle cells to use more fat and less glucose when it contracts. This spares our scarce glycogen stores in our muscles and liver, allowing us to exercise for longer.
If you use coffee as a stimulant to aid your athletic performance bear in mind that it takes time for the caffeine levels to peak in your body. It takes one hour before the caffeine levels get close to peaking and the effect generally lasts for about another 2 hours. If you are racing in a very long event then you will need to keep topping up your caffeine levels.