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Water (Double Boiled) any difference?

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  • #16
    Re: Water (Double Boiled) any difference?

    I have done some internet research, and it confirms my initial thoughts on Oxygen being the main flavor contributing gas, but that it is the least of the dissolved gases in the water, and is driven out by heating.

    Carbon dioxide is the next most important, and is much more soluable in water than Oxygen, but is again driven out by heating.

    The hardness of the water is not affected by heating unlike the gases, but will only concentrate in the system if the water is boiled and the steam consumed to texture milk, as the harness salts arent carried out in the steam.
    So If you mainly do short blacks, and dont texture milk, it is of much less importance.

    Here is some snippits of what I found on the web with a simple search of "water dissolved gases taste" in google.

    A high DO level in a community water supply is good because it makes drinking water taste better. However, high DO levels speed up corrosion in water pipes. For this reason, industries use water with the least possible amount of dissolved oxygen. Water used in very low pressure boilers have no more than 2.0 ppm of DO, but most boiler plant operators try to keep oxygen levels to 0.007 ppm or less.

    DISSOLVED SOLIDS
    Total dissolved solids (TDS) are the sum total of all mineral compounds dissolved in the water. They consist primarily of salts of calcium, magnesium or sodium usually in the form of chlorides, sulfates, or bicarbonates.
    Excessive dissolved solids decrease the effectiveness of a water softener. While softening will greatly improve water for laundering and bathing purposes, high TDS content in water will exhibit a salty or brackish taste. In cases where water is high in TDS or chlorides (over 250 ppm), only reverse osmosis, demineralization, or distillation will significantly improve water quality.

    The following experiment will illustrate that air is dissolved in water.

    Experiment. Place a tumbler of fresh well-water or tap-water in a warm place. After a time, bubbles will be seen collecting on the sides of the glass. This is air which was dissolved in the water. As the water grows warm, it cannot hold so much air in solution and some of it separates.

    Distilled water has a flat taste, because air and other dissolved substances which give water its taste have been removed. It will again dissolve the air on being poured several times from one vessel into another.

    Rain is water which has been evaporated from the surfaces of natural bodies of water, oceans, lakes, and from the land, and is practically free from mineral matter, but contains dissolved gases.

    Water is a nearly universal solvent. It dissolves more substances and these in larger quantities than any other liquid. At a given temperature, water will dissolve only a certain proportion of the various salts and other soluble substances. When the water will take up no more, the solution is said to be saturated. Increasing the temperature generally increases the dissolving power of water for solids and liquids. The reverse is usually true for gases.

    Silver, copper, and tin are not perceptibly dissolved in pure water, but when combined with acid substances, the compounds formed are soluble. These compounds of a metal with an acid are called salts. The salts of copper, zinc, and lead are poisonous. Copper, brass, (an alloy of copper with zinc) tin, solder, and iron are metals easily affected by acids, so that cooking utensils made of these materials should not be used with acid substances like lemon and vinegar.

    All gases will dissolve to a greater or lesser extent in water. As we have seen, oxygen has a low solubility in water, as do nitrogen, argon and some of the other gases present in the atmosphere.

    Carbon dioxide, by contrast, is very soluble in water: 1 m3 of water at 20°C will hold 878 g of pure carbon dioxide. However, carbon dioxide is special for another reason. When carbon dioxide dissolves, it reacts with the water to form bicarbonate and carbonate ions.

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    • #17
      Re: Water (Double Boiled) any difference?

      quote author=68474D50046E484D4E4C5D290 link=1245718204/15#15 date=1246014887]
      A high DO level in a community water supply is good because it makes drinking water taste better.
      [/QUOTE]

      Originally posted by 62464F4F4C4C7662465A4446290 link=1245718204/11#11 date=1245905309
      If when water is boiled the and oxygen has escaped in the process

      Is oxygen then introduced back into the water by stirring with a spoon. As a fish tank pump does ??
      Here is an interesting table I found on the web (at address below)
      Solubility of solutes as a function of temperature
      (mg of solutes per liter of water):
      O2 = oxygen, CO2 = carbon dioxide

      Solute Temperature (Deg C)
      0 20 40 60 80 100
      02 69 43 31 14 0 0
      CO2 3350 1690 970 580 0 0

      http://www.sensorex.com/support/education/DO_education.html

      This table indicates the amount of dissolved atmospheric gasses presumably at a standard atmospheric composition and pressure.

      This table indicates what the equilibrium concentrations are for water at various temperatures. When heating a container of water, by the time it has been heated to 80 degrees C it will have given up any dissolved oxygen and carbon dioxide, what delay if any, in reaching this state is not indicated. I would guess it would not be a long delay.
      If the same container of water was cooled, to re-saturate the water with these solutes would be quite a slow process.
      The solute concentration in the overlying atmosphere and the surface area available for gas exchange would have a bearing on the time required (an aquarium pump or paddle wheel would increase the available surface area for gas exchange).

      Not too dry as a topic I hope?

      Lindsay

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