Subject: Coffee and Caffeine's Frequently Asked Questions

Archive-Name: caffeine-faq
Last-modified: September 14, 1994
Version: 2.1

Frequently Asked Questions about Coffee and Caffeine

Alejandro Lopez-Ortiz 

This group is dedicated to all beverages and products that contain caffeine;
including tea, coffee, chocolate, mate, caffeinated soft drinks, caffeinated
pills, coffee beans, etc.

 1. The Chemistry of Caffeine and related products 
    1. How much caffeine is there in [drink/food/pill]? 
    2. Chemically speaking, what is caffeine? 
    3. Is it true that tea has no caffeine/What is theine, theobromine,
    4. Where can I find a gif of the caffeine molecule? 
    5. Is it true that espresso has less caffeine than regular coffee? 
    6. How does caffeine taste? 
    7. How much theobromine/theophylline there is in ...? 
 2. How to brew the ultimate caffeine drink? 
    1. What is the best temperature for drip coffee? 
    2. Quality of coffee 
    3. Why you should never use percolators
 3. Peripherals and Secondary Storage 
    1. Proper care of Coffee makers... 
    2. How to store coffee? 
    3. Equipment reviews? 
 4. Caffeine and your Health 
    1. What happens when you overdose? 
    2. Studies on the side-effects of caffeine... 
    3. Caffeine and your metabolism. 
 5. Miscellaneous 
    1. How do you pronounce mate? 
    2. How do you spell Colombia/Colombian? 
    3. How do you spell Espresso?
 6. Coffee Recipes and other beverages. 
    1. Espresso 
    2. Capuccino 
    3. How to make your own chocolate 
    4. How to make the best cup of coffee 
    5. Turkish Coffee 
    6. Thai Iced Coffee 
    7. Vietnamese Iced Coffee 
    8. Melya
 7. Administrivia 
    1. List of Contributors 
    2. Copyright 

 1. The Chemistry of Caffeine and related products

    1. How much caffeine is there in [drink/food/pill]? 

      According to the National Soft Drink Association, the
      following is the caffeine content in mgs per 12 oz can of soda: 

      Jolt                    100.0
      Sugar-Free Mr. Pibb     58.8
      Mountain Dew            55.0  (no caffeine in Canada)
      Diet Mountain Dew       55.0
      Mello Yellow            52.8
      Tab                     46.8
      Coca-Cola               45.6
      Diet Cola               45.6
      Shasta Cola             44.4
      Shasta Cherry Cola      44.4
      Shasta Diet Cola        44.4
      Mr. Pibb                40.8
      OK Soda                 40.5
      Dr. Pepper              39.6
      Pepsi Cola              37.2
      Aspen                   36.0
      Diet Pepsi              35.4
      RC Cola                 36.0
      Diet RC                 36.0
      Diet Rite               36.0
      Canada Dry Cola         30.0
      Canada Dry Diet Cola    1.2
      7 Up                    0

      By means of comparison, a 7 oz cup of coffee has the following
      caffeine (mg) amounts, according to Bunker and McWilliams
      in _J Am Diet_ 74:28-32, 1979: 

      Drip                    115-175
      Espresso                100mg of caffeine   
      1 serving (1.5-2oz) 

      Brewed                  80-135
      Instant                 65-100
      Decaf, brewed           3-4
      Decaf, instant          2-3
      tea, iced (12 ozs.)     70
      tea, brewed, imported   60
      tea, brewed, U.S.       40
      tea, instant            30

      The variability in the amount of caffeine in a cup of coffee or
      tea is huge even if prepared by the same person using the same
      equipment and ingredients day after day. 

      Reference Variability in caffeine consumption from coffee and
      tea: Possible significance for epidemiological studies by B.
      Stavric, R. Klassen, B. Watkinson, K. Karpinski, R. Stapley, and
      P. Fried in "Foundations of Chemical Toxicology", Volume 26,
      number 2, pp. 111-118, 1988 and an easy to read overview, 
      Looking for the Perfect Brew by S. Eisenberg, "Science News",
      Volume 133, April 16, 1988, pp. 252-253. 

      Quote from the lab manual:

      Caffeine is present in tea leaves and in coffee to the extent of
      about 4%. Tea also contains two other alkaloids,
      theobromine and theophylline. These last two relax the
      smooth muscles where caffeine stimulates the heart and
      respiratory systems. 

      Steve Dyer says: 

      Theobromine is virtually inactive. Both caffeine and
      theophylline stimulate the heart and respiratory systems and
      relax smooth muscle (such as in the bronchioles).
      Theophylline is somewhat more toxic and somewhat less
      powerful a CNS stimulant than caffeine, but they are more
      similar than different. 

      Other data on caffeine: 

      Cup of coffee    90-150mg
      Instant coffee   60-80mg
      Tea              30-70mg
      Cola             30-45mg
      Chocolate bar    30mg
      Stay-awake pill  100mg
      Vivarin          200mg  
      Cold relief tablet  30mg

      The following information is from Bowes and Church's Food
      values of portions commonly used, by Anna De Planter Bowes.
      Lippincott, Phila. 1989. Pages 261-2: Caffeine. 


      Chocolate                               mg caffeine
        baking choc, unsweetened, Bakers--1 oz(28 g) 25
        german sweet, Bakers -- 1 oz (28 g)           8
        semi-sweet, Bakers -- 1 oz (28 g)            13

      Choc chips
        Bakers -- 1/4 cup (43 g)                     13
        german sweet, Bakers -- 1/4 cup (43 g)       15

      Chocolate bar, Cadbury  -- 1 oz (28 g)         15
      Chocolate milk  8oz                             8

      Jello Pudding Pops, Choc (47 g)                 2
      Choc mousse from Jell-O mix (95 g)              6
      Jello choc fudge mousse (86 g)                 12

      3 heaping teaspoons of choc powder mix          8
      2 tablespoons choc syrup                        5
      1 envelope hot cocoa mix                        5

      Dietary formulas
      ensure, plus, choc, Ross Labs -- 8 oz (259 g)  10
      Cadbury Milk Chocolate Bar

      More stuff:

      Guarana "Magic Power" (quite common in Germany),
      15 ml alcohol with
      5g Guarana Seeds        250.0 mg
      Guarana capsules with
      500 mg G. seeds          25.0 mg / capsule

      (assuming 5% caffeine in seeds as stated in literature)

      Guarana soda pop is ubiquitous in Brazil and often available at
      tropical groceries here. It's really tasty and packs a wallop.
      Guarana wakes you up like crazy, but it doesn't cause coffee

      It is possible that in addition to caffeine, there is some other
      substance in guarana that also produces an effect, since it 'feels'
      different than coffee. Same goes for mate. 

    2. Chemically speaking, what is caffeine?

      Chemical Indexes report:

      RN   58-08-2  REGISTRY
      CN   1H-Purine-2,6-dione, 3,7-dihydro-1,3,7-trimethyl- (9CI)  (CA INDEX NAME)
      CN   Caffeine (8CI)
      CN   1,3,7-Trimethyl-2,6-dioxopurine
      CN   1,3,7-Trimethylxanthine
      CN   7-Methyltheophylline
      CN   Alert-Pep
      CN   Cafeina
      CN   Caffein
      CN   Cafipel
      CN   Guaranine
      CN   Koffein
      CN   Mateina
      CN   Methyltheobromine
      CN   No-Doz
      CN   Refresh'n
      CN   Stim
      CN   Thein
      CN   Theine
      CN   Tri-Aqua

      MF   C8 H10 N4 O2

      The correct name is the first one,
      1H-Purine-2,6-diione,3,7-dihydro-1,3,7-trimethyl- (This is
      the "inverted name") The "uninverted name" is

      Merck Index excerpt... 

      Caffeine: 3,7-dihydro- 1,3,7-trimethyl- 1H-purine-
      2,6-dione; 1,3,7-trimethylxanthine; 1,3,7-trimethyl-
      2,6-dioxopurine; coffeine; thein; guaranine;
      methyltheobromine; No-Doz.

      C8H10N4O2; mol wt 194.19. C 49.48%, H 5.19%, N
      28.85%, O 16.48%.

      Occurs in tea, coffee, mate leaves; also in guarana paste and
      cola nuts: Shuman, U.S. pat. 2,508,545 (1950 to General
      Foods). Obtained as a by-product from the manuf of
      caffeine-free coffee: Barch, U.S. pat. 2,817,588 (1957 to
      Standard Brands); Nutting, U.S. pat. 2,802,739 (1957 to Hill
      Bros. Coffee); Adler, Earle, U.S. pat. 2,933,395 (1960 to
      General Foods).

      Crystal structure: Sutor, Acta Cryst. 11, 453, (1958).
      Synthesis: Fischer, Ach, Ber. 28, 2473, 3135 (1895); Gepner,
      Kreps, J. Gen. Chem. USSR 16, 179 (1946); Bredereck et al.,
      Ber. 83, 201 (1950); Crippa, Crippa, Farmaco Ed. Sci. 10,
      616 (1955); Swidinsky, Baizer, U.S. pats. 2,785,162 and
      2,785,163 (1957 to Quinine Chem. Works); Bredereck,
      Gotsmann, Ber. 95, 1902 (1962).

      Hexagonal prisms by sublimation, mp 238 C. Sublimes 178
      C. Fast sublimation is obtained at 160-165 C under 1mm
      press. at 5 mm distance. d 1.23. Kb at 19 C: 0.7 x 10^(-14).
      Ka at 25 C: <1.0 x 10^(-14). pH of 1% soln 6.9. Aq solns of
      caffeine salts dissociate quickly. Absorption spectrum:
      Hartley, J. Chem. Soc. 87, 1802 (1905). One gram dissolves
      in 46 ml water, 5.5 ml water at 80 C, 1.5 ml boiling water,
      66 ml alcohol, 22 ml alcohol at 60 C, 50 ml acetone, 5.5 ml
      chloroform, 530 ml ether, 100 ml benzene, 22 ml boiling
      benzene. Freely sol in pyrrole; in tetrahydrofuran contg
      about 4% water; also sol in ethyl acetate; slightly in petr
      ether. Soly in water is increased by alkali benzoates,
      cinnamates, citrates, or salicylates.

      Monohydrate, felted needles, contg 8.5% H2O. Efflorescent
      in air; complete dehydration takes place at 80 C. LD50
      orally in rats: 200 mg/kg.

      Acetate, C8H10N4O2.(CH3COOH)2, granules or powder;
      acetic acid odor; acid reaction. Loses acetic acid on
      exposure to air. Soluble in water or alcohol with hydrolysis
      into caffeine and acetic acid. Keep well stoppered. 

      Hydrochloride dihydrate, C8H10N4O2.HCl.2H2O, crystals,
      dec 80-100 C with loss of water and HCl. Sol in water and
      in alcohol with dec.

      Therap Cat: Central stimulant.

      Therap Cat (Vet): Has been used as a cardiac and
      respiratory stimulant and as a diuretic.

    3. Is it true that tea has no caffeine/What is theine,
      theobromine, etc?

      From "Principles of biochemistry", Horton and al, 1993. 

      Caffeine is sometimes called "theine" when it's in tea. This
      is probably due to an ancient misconception that the active
      constituent is different. Theophylline is present only in trace
      amounts. It is more diuretic, more toxic and less speedy. 


      Coffee and tea contain caffeine and theophylline,
      respectively, which are me thylated purine derivatives that
      inhibit cAMP phosphodiesterase.In the presence of these
      inhibitors, the effects of cAMP, and thus the stimulatory
      effects of the hormones that lead to its production, are
      prolonged and intensified. 

      Theobromine and theophylline are two dimethyxanthines that
      have two rather than three methyl groups. Theobromine is
      considerably weaker than caffeine and theophylline, having
      about one tenth the stimulating^? effect of either.

      Theobromine is found in cocoa products, tea (only in very small
      amounts) and kola nuts, but is not found in coffee. In cocoa, its
      concentration is generally about 7 times as great as caffeine.
      Although, caffeine is relatively scarce in cocoa, its mainly
      because of theobromine that cocoa is "stimulating".

      Theophylline is found in very small amounts in tea, but has a
      stronger effect on the heart and breathing than caffeine. It often
      the drug of choice in treating asthma bronchitis and
      emphysema. The theophylline found in medicine is made from
      extracts from coffee or tea.

    4. Where can I find a gif of the caffeine molecule? 

      Caffeine = 1,3,7-Trimethylxanthine 

    5. Is it true that espresso has less caffeine than regular coffee?