When looking for a caffeine jolt, should one turn to coffee or tea? Some may tell you coffee has more caffeine than tea, and some may say the tea contains more caffeine than coffee. Believe everyone! They are both right! Gram per gram, tea leaves contain more caffeine than coffee beans, (Tea leaves contain about 3.5% caffeine, coffee beans contain 1.1% to 2.2% caffeine - Arabica 1.1% and Robusta 2.2%). Liter per liter however, brewed coffee contains more caffeine than brewed tea. This occurs because tea is properly made with about 15grams leaves per liter water, and for coffee about 50grams beans per liter water.
Decaffeinated coffee, some see it as a necessity, some see it as an abomination, some as a convenient luxury, some a necessary evil. Decaffeinated coffee is in significant demand and the methods of decaffeination, while still not what I would call adequate, are improving. The key to coffee decaffeination is using a solution that selectively dissolves caffeine into solution while leaving behind the other coffee flavor and aroma compounds. Unfortunately, none of the decaffeination methods or chemicals are totally selective for caffeine and therefore they all do affect the coffee flavor. The methods primarily take advantage of the fact that the caffeine is one of the most easily solublized compounds in coffee. Methylene chloride, ethyl acetate, and carbon dioxide liquid are commonly used as these agents and can produce coffee with only 2-3% of its original caffeine left. When talking coffee decaffeination one will usually hear of three methods, the European Process (EP), the Swiss Water Process (SWP), and the Natural Processes (NP).
In the European process, the unroasted green beans are steamed and then washed with methylene chloride, rinsed and dried. The methylene chloride removes most of the caffeine and some of the other flavor compounds. The same process using ethyl acetate is sometimes referred to as a "Natural Process" because ethyl acetate can be acquired from some fruits and is thus "natural". Other Natural processes are the CO2 method and the Sparkling Water Process. In the CO2 method, the beans are soaked in highly compressed carbon dioxide, removing the caffeine. The CO2 is then passed through activated carbon filters which remove the caffeine from the CO2. The sparkling water process is similar, but instead of using carbon filters to remove the caffeine from the CO2, the CO2 is washed free of caffeine with water in a separate tank.
The Swiss water process is a little more difficult to understand. Beans are soaked in hot water to remove all compounds in the coffee. These beans (which are little more than cellulose walls) are discarded. The flavor-charged water, is then passed through activated carbon filters to remove the caffeine. Then a new batch of green beans are soaked in this caffeineless flavor-charged water. Because all the compounds in the bean except caffeine, are in equilibrium with the caffeineless flavor-charged water, there is no concentration difference and they stay in the bean. For the caffeine, however, there is a concentration difference, and thus (to achieve equilibrium) the caffeine diffuses out of the bean into the water. The beans have thus been decaffeinated.
Caffeine, while famous for its ability to conjure and sustain mental alertness, this odorless, bitter alkaloid has more effects then many are aware of. All of caffeine's effects are subject to individual differences in how one's body responds to caffeine and all bodies respond differently. Caffeine sensitivity is affected by body weight and build, tolerance, metabolism, hormonal status, whether he/she smokes or takes medication, and liver function. The onset of caffeine's effects occur 5 - 45 minutes after ingestion, and typically last one and a half to five hours.
A good summary of the effects appears in The Pharmacological Basis of Therapeutics by Dr. J. Murdoch Ritchie: it reads caffeine produces " a more rapid and clearer flow of thought....After taking caffeine one is capable of greater sustained intellectual effort and a more perfect association of ideas. There is also a keener appreciation of sensory stimuli, and motor activity is increased; typists, for example, work faster and with fewer errors." Additionally, heart rate increases, respiration increases, metabolic rate increases, blood vessels dilate, stomach acid and urine are produced, smooth muscles are relaxed, and movement of fluid and solid wastes from the body are promoted. Such effects are after about one or two cups of coffee (around 200mg caffeine). These effects generally increase as one's caffeine consumption increases, however, the sleep deprivation that caffeine may led to has its own effects which may result in one being mentally rapid and alert, but with little clarity and focus. If large doses of caffeine are taken (around 10 cups of coffee drunk quickly, 1gram caffeine ), mental confusion, headache, chills, fever, irregular heartbeats, and vomiting may result. Caffeine is estimated to be lethal around 4 to 10 grams).
Many have their own idiosyncratic side effects of caffeine due to its primary effects. For example, as stated above, caffeine relaxes smooth muscles and increases stomach acid production. In some people caffeine relaxes the sphincter muscles at the top of the stomach enough to allow the now increased level of stomach acid to backup into their throat causing heartburn. Many view caffeine much like a tool for increased productivity, creativity, or wit. Here are a few quotes extolling the effects of caffeine.
Without my morning coffee I'm just like a dried up piece of roast goat. -Johann Sebastian Bach
For fifteen days I struggled to prove that no functions analogous to those I have since called Fuchsian functions could exist; I was then very ignorant. Every day I sat down at my work table where I spent an hour or two; I tried a great number of combinations and arrived at no result. One evening, contrary to my custom, I took black coffee; I could not go to sleep; ideas swarmed up in clouds; I sensed them clashing until, to put it so, a pair would hook together to form a stable combination. By morning I had established the existence of a class of Fuchsian functions, those derived from the hypergeometric series. I had only to write up the results which took me a few hours. - Henri Poincare,
"Science et Methode": Coffee: creative lighter fluid. --Floyd Maxwell (1957-)
Last week we saw that a cup of coffee typically has more caffeine than a cup of tea. So now we follow up with whether regularly brewed coffee or espresso contains more caffeine. Coffee is properly brewed at about 50grams per liter (although this is quite strong to many), while espresso is brewed at around 233grams per liter (assuming 7grams per each 1 fluid ounce shot). Therefore espresso is more concentrated with coffee solubles and has about four to five times the concentration of caffeine compared to regularly brewed coffee (per unit volume). Now however we must consider portion size, because even though I sometimes think I could really go for 16ounces of espresso (approximately 16 shots), It's doubtful I would finish it. While I could probably drink 16ounces of regularly brewed coffee without even realizing it or giving it time to cool.