Friday, October 16, 2015

Why do some foods feel too hot compared to others?

Why do some foods feel too hot while others don't -- even though you heated them in the oven for the same length of time? The answer can be found in the heat content or specific heat, which is the amount of heat per mass unit necessary to raise its temperature by a degree. [Note: The specific heat of water is 1 cal/gm-degC, which is the highest for any liquid we have, which makes it one of the best heat transfer agents.]


You will notice from the table below asparagus has a higher specific heat (by ~ 14%) than potato. Why do you find that your asparagus has gone cold while your baked potato is still very hot to burn your tongue although they came from the same micro  woven? The clue is in the density difference. Potato is almost twice (actually 1.54) as heavy as asparagus for the same volume. It has a density of approx. 43 lb/ft3 compared to asparagus which has a density of 28 lb/ft3. Therefore, potato would require about 54% more heat compared to asparagus to get heated by a single degree rise in temperature. Thus, at steady state, for the same heat provided to the same volume of potato and asparagus, the temperature rise in potato is only about 75% of asparagus. And yet, when it is served to you it feels hotter than the asparagus. Why?
Once you take food out of the oven, heat transfer with air or the environment controls its cooling process. A substance with a larger surface area cools faster. Because of its high aspect ratio (i.e., length to diameter), and thus higher surface area for the same volume, asparagus cools down much faster than round shaped potatoes.
So, it is not only specific heat but also the density and heat transfer that are at the heart of why asparagus can be eaten earlier than baked potato when served in the dinner table.


Kapish?




  Specific Heat above Freezing Specific Heat below Freezing
  (btu/lboF) (kJ/kgoC) (kcal/kgoC) (btu/lboF) (kJ/kgoC) (kcal/kgoC)
Apples 0.87 3.64 0.87 0.42 1.76 0.42
Apricots. fresh 0.88 3.68 0.88 0.43 1.8 0.43
Artichokes 0.87 3.64 0.87 0.42 1.76 0.42
Asparagus 0.94 3.94 0.94 0.45 1.88 0.45
Asparagus beans 0.88 3.68 0.88 0.43 1.8 0.43
Avocados 0.72 3.01 0.72 0.37 1.55 0.37
Bacon   2        
Bananas 0.8 3.35 0.8 0.4 1.67 0.4
Barracuda 0.8 3.35 0.8 0.4 1.67 0.4
Bass 0.82 3.43 0.82 0.41 1.72 0.41
Beef, carcass 0.68 2.85 0.68 0.48 2.01 0.48
Beef, flank 0.56 2.34 0.56 0.32 1.34 0.32
Beef, hamburger   3.52        
Beef, loin 0.66 2.76 0.66 0.35 1.47 0.35
Beef, rib 0.67 2.81 0.67 0.36 1.51 0.36
Beef, round 0.74 3.1 0.74 0.38 1.59 0.38
Beef, rump 0.62 2.6 0.62 0.34 1.42 0.34
Beef, shanks 0.76 3.18 0.76 0.39 1.63 0.39
Beef, corned 0.63 2.64 0.63 0.34 1.42 0.34
Beets 0.9 3.77 0.9 0.43 1.8 0.43
Blackberry 0.87 3.64 0.87 0.42 1.76 0.42
Blueberries 0.87 3.64 0.87 0.42 1.76 0.42
Brains 0.84 3.52 0.84 0.41 1.72 0.41
Broccoli 0.92 3.85 0.92 0.44 1.84 0.44
Brussels sprouts 0.88 3.68 0.88 0.43 1.8 0.43
Butter 0.65 2.72 0.65 0.34 1.42 0.34
Butter-fish 0.77 3.22 0.77 0.39 1.63 0.39
Cabbage 0.94 3.94 0.94 0.45 1.88 0.45
Candy 0.93 3.89 0.93 0.93 3.89 0.93
Carp 0.82 3.43 0.82 0.41 1.72 0.41
Carrots 0.91 3.81 0.91 0.44 1.84 0.44
Cauliflower 0.93 3.89 0.93 0.44 1.84 0.44
Celery 0.94 3.94 0.94 0.45 1.88 0.45
Chard 0.93 3.89 0.93 0.43 1.8 0.43
Cheese, cottage   3.27        
Cherries, sour 0.88 3.68 0.88 0.41 1.72 0.41
Cherries, sweet 0.84 3.52 0.84 0.4 1.67 0.4
Chicken, squab 0.8 3.35 0.8 0.39 1.63 0.39
Chicken, broilers 0.77 3.22 0.77 0.38 1.59 0.38
Chicken, fryers 0.74 3.1 0.74 0.35 1.47 0.35
Chicken, hens 0.65 2.72 0.65 0.44 1.84 0.44
Chicken, capons 0.88 3.68 0.88 0.41 1.72 0.41
Chocolate (aprox.)   1.6        
Clams, meat only 0.84 3.52 0.84 0.36 1.51 0.36
Coconut, meat and milk 0.68 2.85 0.68 0.45 1.88 0.45
Coconut, milk only 0.95 3.98 0.95 0.42 1.76 0.42
Codfish 0.86 3.6 0.86 0.39 1.63 0.39
Cod Roe 0.76 3.18 0.76 0.39 1.63 0.39
Cow-peas, fresh 0.73 3.06 0.73 0.22 0.92 0.22
Cow-peas, dry 0.28 1.17 0.28 0.41 1.72 0.41
Crabs 0.84 3.52 0.84 0.41 1.72 0.41
Crab apples 0.85 3.56 0.85 0.43 1.8 0.43
Cranberries 0.9 3.77 0.9 0.38 1.59 0.38
Cream 0.9 3.77 0.9 0.45 1.88 0.45
Cucumber 0.98 4.1 0.98 0.45 1.88 0.45
Currants 0.97 4.06 0.97 0.45 1.88 0.45
Dandelion greens 0.88 3.68 0.88 0.43 1.8 0.43
Dates 0.2 0.84 0.2 0.01 0.03 0.01
Eels 0.77 3.22 0.77 0.39 1.63 0.39
Eggs 0.76 3.18 0.76 0.4 1.67 0.4
Eggplant 0.94 3.94 0.94 0.45 1.88 0.45
Endive 0.95 3.98 0.95 0.45 1.88 0.45
Figs, fresh 0.82 3.43 0.82 0.41 1.72 0.41
Figs, dried 0.39 1.63 0.39 0.26 1.09 0.26
Figs, candied 0.37 1.55 0.37 0.26 1.09 0.26
Fish, canned   3.35        
Fish, fresh   3.6        
Flounders 0.86 3.6 0.86 0.42 1.76 0.42
Flour 0.38 1.59 0.38 0.28 1.17 0.28
Frogs, legs 0.88 3.68 0.88 0.44 1.84 0.44
Garlic 0.79 3.31 0.79 0.4 1.67 0.4
Gizzards 0.78 3.27 0.78 0.39 1.63 0.39
Goose 0.61 2.55 0.61 0.34 1.42 0.34
Gooseberry 0.86 3.6 0.86 0.42 1.76 0.42
Granadilla 0.84 3.52 0.84 0.41 1.72 0.41
Grapefruit 0.91 3.81 0.91 0.44 1.84 0.44
Grapes 0.86 3.6 0.86 0.42 1.76 0.42
Grape juice 0.82 3.43 0.82 0.41 1.72 0.41
Guavas 0.86 3.6 0.86 0.42 1.76 0.42
Guinea hen 0.75 3.14 0.75 0.38 1.59 0.38
Haddock 0.85 3.56 0.85 0.42 1.76 0.42
Halibut 0.8 3.35 0.8 0.4 1.67 0.4
Herring, smoked 0.71 2.97 0.71 0.37 1.55 0.37
Horseradish, fresh 0.79 3.31 0.79 0.4 1.67 0.4
Horseradish, prepared 0.88 3.68 0.88 0.43 1.8 0.43
Ice cream 0.74 3.1 0.74 0.4 1.67 0.4
Kale 0.89 3.73 0.89 0.43 1.8 0.43
Kidneys 0.81 3.39 0.81 0.4 1.67 0.4
Kidney beans, dried 0.28 1.17 0.28 0.23 0.96 0.23
Kohlrabi 0.92 3.85 0.92 0.44 1.84 0.44
Kumquats 0.85 3.56 0.85 0.41 1.72 0.41
Lamb, carcass 0.73 3.06 0.73 0.38 1.59 0.38
Lamb, leg 0.71 2.97 0.71 0.37 1.55 0.37
Lamb, rib cut 0.61 2.55 0.61 0.34 1.42 0.34
Lamb, shoulder 0.67 2.81 0.67 0.35 1.47 0.35
Lard 0.54 2.26 0.54 0.31 1.3 0.31
Leeks 0.91 3.81 0.91 0.44 1.84 0.44
Lemons 0.91 3.81 0.91 0.44 1.84 0.44
Lemon juice 0.92 3.85 0.92 0.44 1.84 0.44
Lettuce 0.96 4.02 0.96 0.45 1.88 0.45
Lima beans 0.73 3.06 0.73 0.38 1.59 0.38
Limes 0.89 3.73 0.89 0.43 1.8 0.43
Lime juice 0.93 3.89 0.93 0.44 1.84 0.44
Litchi fruits, dried 0.39 1.63 0.39 0.26 1.09 0.26
Liver, raw beef   3.5        
Lobsters 0.82 3.43 0.82 0.41 1.72 0.41
Loganberries 0.86 3.6 0.86 0.42 1.76 0.42
Loganberry juice 0.91 3.81 0.91 0.44 1.84 0.44
Milk, cow - whole pasteurized 0.9 3.77 0.9 0.47 1.97 0.47
Milk, dry no fat   1.52        
Mushrooms, fresh 0.93 3.89 0.93 0.44 1.84 0.44
Mushrooms, dried 0.3 1.26 0.3 0.23 0.96 0.23
Muskmelons 0.94 3.94 0.94 0.45 1.88 0.45
Nectarines 0.86 3.6 0.86 0.42 1.76 0.42
Nuts 0.28 1.17 0.28 0.24 1 0.24
Olives, green 0.8 3.35 0.8 0.4 1.67 0.4
Onions 0.9 3.77 0.9 0.43 1.8 0.43
Onion, Welsh 0.91 3.81 0.91 0.44 1.84 0.44
Oranges, fresh 0.9 3.77 0.9 0.43 1.8 0.43
Orange juice 0.89 3.73 0.89 0.43 1.8 0.43
Oysters 0.84 3.52 0.84 0.41 1.72 0.41
Peaches, Georgina 0.87 3.64 0.87 0.42 1.76 0.42
Peaches, North Carolina 0.89 3.73 0.89 0.43 1.8 0.43
Peaches, Maryland 0.9 3.77 0.9 0.43 1.8 0.43
Peaches, New Jersey 0.91 3.81 0.91 0.44 1.84 0.44
Peach juice fresh 0.89 3.73 0.89 0.43 1.8 0.43
Pears, Bartlet 0.89 3.73 0.89 0.43 1.8 0.43
Pears, Beurre Bosc 0.85 3.56 0.85 0.41 1.72 0.41
Pears. dried 0.39 1.63 0.39 0.26 1.09 0.26
Peas, young 0.85 3.56 0.85 0.41 1.72 0.41
Peas, medium 0.81 3.39 0.81 0.4 1.67 0.4
Peas, old 0.88 3.68 0.88 0.43 1.8 0.43
Peas, split 0.28 1.17 0.28 0.23 0.96 0.23
Peppers, ripe 0.91 3.81 0.91 0.44 1.84 0.44
Perch 0.82 3.43 0.82 0.41 1.72 0.41
Persimmons 0.72 3.01 0.72 0.37 1.55 0.37
Pheasant 0.75 3.14 0.75 0.36 1.51 0.36
Pickerel 0.84 3.52 0.84 0.41 1.72 0.41
Pickles, sweet 0.82 3.43 0.82 0.41 1.72 0.41
Pickles, sour and dill 0.96 4.02 0.96 0.45 1.88 0.45
Pickles, sweet mixed 0.78 3.27 0.78 0.29 1.21 0.29
Pickles, sour mixed 0.95 3.98 0.95 0.45 1.88 0.45
Pig's feet, pickled 0.5 2.09 0.5 0.31 1.3 0.31
Pike 0.84 3.52 0.84 0.41 1.72 0.41
Pineapple, fresh 0.88 3.68 0.88 0.43 1.8 0.43
Pineapple, sliced or crushed 0.82 3.43 0.82 0.41 1.72 0.41
Pineapple, juice 0.9 3.77 0.9 0.43 1.8 0.43
Plums 0.89 3.73 0.89 0.43 1.8 0.43
Pomegranate 0.85 3.56 0.85 0.41 1.72 0.41
Pompano 0.77 3.22 0.77 0.39 1.63 0.39
Porgy 0.81 3.39 0.81 0.4 1.67 0.4
Pork, bacon 0.36 1.51 0.36 0.25 1.05 0.25
Pork, ham 0.62 2.6 0.62 0.34 1.42 0.34
Pork, loin 0.66 2.76 0.66 0.35 1.47 0.35
Pork, shoulder 0.59 2.47 0.59 0.33 1.38 0.33
Pork, spareribs 0.62 2.6 0.62 0.34 1.42 0.34
Pork, smoked ham 0.65 2.72 0.65 0.35 1.47 0.35
Pork, salted 0.31 1.3 0.31 0.24 1 0.24
Potatoes 0.82 3.43 0.82 0.41 1.72 0.41
Prickly pears 0.91 3.81 0.91 0.43 1.81 0.43
Prunes 0.81 3.39 0.81 0.4 1.67 0.4
Pumpkin 0.92 3.85 0.92 0.44 1.84 0.44
Quinces 0.88 3.68 0.88 0.43 1.8 0.43
Rabbit 0.76 3.18 0.76 0.39 1.63 0.39
Radishes 0.95 3.98 0.95 0.45 1.88 0.45
Raisins 0.39 1.63 0.39 0.26 1.09 0.26
Raspberries, black 0.85 3.56 0.85 0.41 1.72 0.41
Raspberries, red 0.89 3.73 0.89 0.43 1.8 0.43
Raspberry juice, black 0.91 3.81 0.91 0.44 1.84 0.44
Raspberry juice, red 0.93 3.89 0.93 0.44 1.84 0.44
Reindeer 0.73 3.06 0.73 0.37 1.55 0.37
Rhubarb 0.96 4.03 0.96 0.45 1.88 0.45
Rose Apple 0.89 3.73 0.89 0.43 1.8 0.43
Rutabagas 0.91 3.81 0.91 0.44 1.84 0.44
Salmon 0.71 2.97 0.71 0.37 1.55 0.37
Sand dab 0.86 3.6 0.86 0.42 1.76 0.42
Sapodilla 0.91 3.81 0.91 0.44 1.84 0.44
Sapote 0.73 3.06 0.73 0.37 1.55 0.37
Sauerkraut 0.93 3.89 0.93 0.44 1.84 0.44
Sausage, beef and pork 0.56 2.34 0.56 0.32 1.34 0.32
Sausage, Bratwurst 0.71 2.97 0.71 0.37 1.55 0.37
Sausage, Bologna 0.71 2.97 0.71 0.37 1.55 0.37
Sausage, Frankfurter 0.69 2.89 0.69 0.36 1.51 0.36
Sausage, salami 0.45 1.88 0.45 0.28 1.17 0.28
Sardines 0.77 3.22 0.77 0.39 1.63 0.39
Shad 0.76 3.18 0.76 0.39 1.63 0.39
Shrimp 0.83 3.48 0.83 0.41 1.72 0.41
Skim milk   4        
Spanish mackerel 0.73 3.06 0.73 0.39 1.63 0.39
Starch   1.75        
Strawberries 0.95 3.98 0.95 0.45 1.88 0.45
Strawberry juice 0.79 3.31 0.79 0.39 1.63 0.39
String beans 0.91 3.81 0.91 0.44 1.84 0.44
Sturgeon, raw 0.83 3.48 0.83 0.41 1.72 0.41
Sturgeon, smoked 0.71 2.97 0.71 0.37 1.55 0.37
Sugar apple, fresh 0.79 3.31 0.79 0.39 1.63 0.39
Sweet potatoes 0.75 3.14 0.75 0.38 1.59 0.38
Swordfish 0.8 3.35 0.8 0.4 1.67 0.4
Terrapin 0.8 3.35 0.8 0.4 1.67 0.4
Tomatoes, red 0.95 3.98 0.95 0.45 1.88 0.45
Tomatoes, green 0.96 4.02 0.96 0.45 1.88 0.45
Tomato, juice 0.95 3.98 0.95 0.45 1.88 0.45
Tongue, beef 0.74 3.1 0.74 0.38 1.59 0.38
Tongue, calf 0.79 3.31 0.79 0.4 1.67 0.4
Tongue, lamb 0.76 3.18 0.76 0.38 1.59 0.38
Tongue, pork 0.74 3.1 0.74 0.39 1.63 0.39
Tongue, sheep 0.69 2.89 0.69 0.36 1.51 0.36
Tomato soup, concentrate   3.67        
Tripe, beef 0.83 3.48 0.83 0.41 1.72 0.41
Tripe, pickled 0.89 3.73 0.89 0.43 1.8 0.43
Trout 0.82 3.43 0.82 0.41 1.72 0.41
Tuna 0.76 3.18 0.76 0.39 1.63 0.39
Turkey 0.67 2.81 0.67 0.35 1.47 0.35
Turnips 0.93 3.89 0.93 0.44 1.84 0.44
Turtle 0.84 3.52 0.84 0.41 1.72 0.41
Veal, carcass 0.74 3.1 0.74 0.38 1.59 0.38
Veal, flank 0.65 2.72 0.65 0.35 1.47 0.35
Veal, loin 0.75 3.14 0.75 0.38 1.59 0.38
Veal, rib 0.73 3.06 0.73 0.37 1.54 0.37
Veal, shank 0.77 3.22 0.77 0.39 1.63 0.39
Veal, quarter 0.74 3.1 0.74 0.38 1.59 0.38
Venison 0.78 3.27 0.78 0.39 1.63 0.39
Watercress 0.95 3.98 0.95 0.45 1.88 0.45
Watermelon 0.94 3.94 0.94 0.45 1.88 0.45
Whitefish 0.76 3.18 0.76 0.39 1.63 0.39
Yams 0.78 3.27 0.78 0.39 1.63 0.39

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