question: Why can you burn coffee, but you can't burn tea or water?
comment: Typically a pot of coffee sits on a heater after there is coffee in the water. Prolonged exposure to heat, changes the chemical compounds in the coffee, making it bitter. Tea can be burned if you leave it on the burner that way, but you don't typically have a teapot that is being heated while there is tea in it. Hot water goes on leaves. Water can't burn, because it evaporates.
passages: Tea also contains theanine and the stimulant caffeine at about 3% of its dry weight, translating to between 30 mg and 90 mg per 8 oz (250 ml) cup depending on type, brand and brewing method. Tea also contains small amounts of theobromine and theophylline. Dry tea has more caffeine by weight than dry coffee; nevertheless, more dry coffee than dry tea is used in typical drink preparations, which results in a cup of brewed tea containing significantly less caffeine than a cup of coffee of the same size.
   Caffeine constitutes about 3% of tea's dry weight, translating to between and per 8-oz (250-ml) cup depending on the type, brand, and brewing method. A study found that the caffeine content of of black tea ranged from , while the caffeine content of of green tea ranged from , reflecting a significant difference. Tea also contains small amounts of theobromine and theophylline, which are stimulants, and xanthines similar to caffeine.
   A subtler issue is "which" solubles are dissolved – this depends on solubility of different substances at different temperatures, changes over the course of extraction (different substances are extracted during the first 1% of extraction than in the period from 19% extraction to 20% extraction), and is primarily affected by "temperature."
   Coffee beans must be ground and brewed to create a beverage. The criteria for choosing a method include flavor and economy. Almost all methods of preparing coffee require that the beans be ground and then mixed with hot water long enough to allow the flavor to emerge but not so long as to draw out bitter compounds. The liquid can be consumed after the spent grounds are removed. Brewing considerations include the fineness of grind, the way in which the water is used to extract the flavor, the ratio of coffee grounds to water (the brew ratio), additional flavorings such as sugar, milk, and spices, and the technique to be used to separate spent grounds. Ideal holding temperatures range from to as high as and the ideal serving temperature is . The recommended brew ratio for non-espresso coffee is around 55 to 60 grams of grounds per litre of water, or two level tablespoons for a 5- or 6-ounce cup.
   In general, dark-roast coffee has very slightly less caffeine than lighter roasts because the roasting process reduces caffeine content of the bean by a small amount.
  
  Section::::Products.:Beverages.:Tea.
  
  Tea contains more caffeine than coffee by dry weight. A typical serving, however, contains much less, since less of the product is used as compared to an equivalent serving of coffee. Also contributing to caffeine content are growing conditions, processing techniques, and other variables. Thus, teas contain varying amounts of caffeine.
   The usual ratio of coffee to water for the style of coffee most prevalent in Europe, America, and other Westernized nations (evident in publications such as textbooks on coffee and instruction manuals for drip-brew machines) is between one and two tablespoons of ground coffee per six ounces (180 millilitres) of water; the full two tablespoons per six ounces tends to be recommended by experienced coffee lovers. A more exact weight ratio of 1:17 coffee and water is also used in publications.
   BULLET::::- Mate is a drink popular in many parts of South America. Its preparation consists of filling a gourd with the leaves of the South American holly yerba mate, pouring hot but not boiling water over the leaves, and drinking with a straw, the bombilla, which acts as a filter so as to draw only the liquid and not the yerba leaves.
  
  BULLET::::- Guaraná is a soft drink originating in Brazil made from the seeds of the Guaraná fruit.
  
  BULLET::::- The leaves of "Ilex guayusa", the Ecuadorian holly tree, are placed in boiling water to make a guayusa tea.
  
  Section::::Products.:Chocolate.
   Tea contains small amounts of theobromine and slightly higher levels of theophylline than coffee. Preparation and many other factors have a significant impact on tea, and color is a very poor indicator of caffeine content. Teas like the pale Japanese green tea, "gyokuro", for example, contain far more caffeine than much darker teas like "lapsang souchong", which has very little.
  
  Section::::Products.:Beverages.:Soft drinks and energy drinks.
   While most tea is prepared using hot water, it is also possible to brew a beverage from tea using room temperature or cooled water. This requires longer steeping time to extract the key components, and produces a different flavour profile. Cold brews use about 1.5 times the tea leaves that would be used for hot steeping, and are refrigerated for 4–10 hours. The process of making cold brew tea is much simpler than that for cold brew coffee.
   The UK recognises six fire classes:
  
  BULLET::::- Class A fires involve organic solids such as paper and wood.
  
  BULLET::::- Class B fires involve flammable or combustible liquids, including petrol, grease, and oil.
  
  BULLET::::- Class C fires involve flammable gases.
  
  BULLET::::- Class D fires involve combustible metals.
  
  BULLET::::- Class E fires involve electrical equipment/appliances.
  
  BULLET::::- Class F fires involve cooking fat and oil.
   Because the ground coffee beans in cold-brewed coffee never come into contact with heated water, the process of leaching flavor from the beans produces a chemical profile different from conventional brewing methods. Coffee beans contain a number of constituent parts that are more soluble at higher temperatures, such as caffeine, oils and fatty acids. Brewing at a lower temperature results in lower acidity and lower caffeine content when brewed in equal volume. It is around 65 to 70 percent less acidic than hot drip coffee or espresso, per part. Although less caffeine is extracted with the cold brew method, a higher coffee-to-water ratio is often used, between 2 and 2 1/2 times. This may compensate for this difference in solubility, resulting in a brew with equal, if not more, caffeine (although this is unlikely).
   In discussing the proper preparation of both coffee and tea Abbott offers varied opinions on the worthiness of the drinks. Regarding coffee: "M.Payen proves that coffee, slightly roasted, contains the maximum of aroma, weight, and nutrition. He declares coffee to be nutritious, as it contains a large quantity of azote, three times as much nutriment as tea, and more than twice the nourishment of soup."
   Cold brewing, also called "cold water extraction" or "cold pressing," is the process of steeping coffee grounds in water at cool temperatures for an extended period. Coarse-ground beans are soaked in water for a prolonged period of time, for 12 to 24 hours.
   While brewing methods vary widely by tea and individual preferences, 1 teaspoon of looseleaf tea is recommended for every 150 ml (5.07 oz) of water. Ideal water temperature for this type of tea is between and . For the first and second brewing, leaves should be steeped for around one minute. It is also recommended that the tea cup or tea pot used be rinsed with hot water prior to brewing the tea to warm the vessels. When brewed, gunpowder tea is a yellow color.
  
  Section::::Use in the Maghreb.
   BULLET::::- Freshly boiling water is poured into the pot to within 4–6 mm of the brim. Allow 20 seconds for water to cool.
  
  BULLET::::- The water should be similar to the drinking water where the tea will be consumed.
  
  BULLET::::- Brewing time is six minutes.
  
  BULLET::::- The brewed tea is then poured into a white porcelain or glazed earthenware bowl.
  
  BULLET::::- If a large bowl is used, it must have a capacity of 380 ml and weigh 200 g (±20 g).
  
  BULLET::::- If a small bowl is used, it must have a capacity of 200 ml and weigh 105 g (±20 g).
   Section::::Water power.
   Ignition normally takes place in the dead component of the fine fuels. Three distinct steps must be considered in this ignition process. 
  
  They are:
  
  BULLET::::- A firebrand must come into contact with the dead fuel.
  
  BULLET::::- The fuel particle must be dry.
  
  BULLET::::- The temperature of the fuel particle must be raised to the kindling point which is about 380 degrees Celsius.
  
  Living material in the fine fuel complex reduces the efficiency of ignition. Therefore, an adjustment to the ignition component is made based on the percentage of live fuel (herbaceous vegetation) in the fine fuel complex. 
   Depending on the type of coffee and method of preparation, the caffeine content of a single serving can vary greatly. The caffeine content of a cup of coffee varies depending mainly on the brewing method, and also on the coffee variety. According to the USDA National Nutrient Database, an 8-ounce (237 ml) cup of "coffee brewed from grounds" contains 95 mg caffeine, whereas an espresso (25 ml) contains 53 mg.
  
  According to an article in the "Journal of the American Dietetic Association", coffee has the following caffeine content, depending on how it is prepared:
   1806 Coffee percolator
  
  BULLET::::- A coffee percolator is a type of pot used to brew coffee. In the case of coffee-brewing the solvent is water, the permeable substance is the coffee grounds, and the soluble constituents are the chemical compounds that give coffee its color, taste, and aroma. In 1806, Benjamin Thompson Rumford invented the percolating coffee pot with a metal sieve to strain away the grounds.
  
  1808 Lobster trap
   Water temperature is subtler but crucial to the proper extraction of flavor from the ground coffee, as it affects the proportions in which solubles are extracted – one wishes to extract the desired flavors as much as possible, and the undesirable flavors as little as possible. The recommended brewing temperature range of coffee is 91–94 °C (195–202 °F), which is a trade-off between these goals. If cooler, some of the solubles that make up the flavor will not be extracted. If the water is too hot, some undesirable, bitter, elements will be extracted, adversely affecting the taste. Note that this desired temperature range is slightly below the boiling point of water (100 °C or 212 °F at standard pressure), so coffee is best made with water that has been allowed to come off the boil slightly. Another consideration is the difference between the temperature of the water and the temperature of the coffee slurry: for example, certain brewing methods (e.g., manual pourover) can result in losing a significant amount of heat to the atmosphere during the brewing process.
   The Scottish botanist and explorer David Douglas stayed with the Lymans between his historic climb to the summit of Mauna Loa, and his death exploring Mauna Kea in 1834. Mrs. Lyman made a note in her diary about the unusual customs of drinking hot coffee, tea, and "English dinners".
   A popular caffeinated infusion is mate, made from the leaves of the native yerba mate plant. In Brazil, the plant is called "erva-mate" or simply "mate", and the hot beverage drunk from a calabash gourd is called "chimarrão", typically associated with the southernmost state, Rio Grande do Sul. Mate is a popular beverage in other South American countries as well, specially around the people that lives in the southern region, which comprises the named Gaucho culture, or the culture from the Pampas. Argentina, Paraguay, and Uruguay. Specially in the Paraguayan and in a few parts of the northern Argentinian border, the mate is also drunk infused in cold water along the daytime, and receives the name of Terere.
   BULLET::::- "The Industrial Revolution was neither Industrial nor a Revolution. Discuss."
  
  Section::::Ongoing gags.:Mannerisms.:Ethnic and religious references.
   Cold brew coffee is made by steeping coarsely ground beans in cold water for several hours, then filtering them. This results in a brew lower in acidity than most hot-brewing methods.
  
  Section::::Processing.:Nutrition.
  
  Brewed coffee from typical grounds prepared with tap water contains 40 mg caffeine per 100 gram and no essential nutrients in significant content. In espresso, however, likely due to its higher amount of suspended solids, there are significant contents of magnesium, the B vitamins, niacin and riboflavin, and 212 mg of caffeine per 100 grams of grounds.
  
  Section::::Processing.:Serving.
   Physically speaking, tea has properties of both a solution and a suspension. It is a solution of all the water-soluble compounds that have been extracted from the tea leaves, such as the polyphenols and amino acids, but is a suspension when all of the insoluble components are considered, such as the cellulose in the tea leaves.
  
presuppositions: Tea can't be burned.
corrections: Tea is only burned when there is no longer any water to prevent the tea from burning. 
raw_presuppositions: Tea can't be burned. Tea can't be burned.
raw_corrections: Tea is only burned when there is no longer any water to prevent the tea from burning.  Tea can be burned but there is typically no teapot that is being heated while there is tea in it.