What is water?
Soaking water is a common traditional auxiliary material of Cantonese pastry. The method comprises the following steps: boiling grandfathers with plant ash and soaking them in water for one day, and taking supernatant to obtain an alkaline solution with a PH value of 12.6. The main components of plant ash are potassium carbonate and sodium carbonate. In the absence of modern chemical alkali in history, the plant alkali prepared by this indigenous method has to be used.
The water used now is not plant ash, but an alkaline mixture made of potassium carbonate and sodium carbonate as the main components, supplemented by carbonate or polyphosphate according to the composition and principle of plant ash, which is the same as the water used in plant ash in function, so it is still called water. If only potassium carbonate and sodium carbonate are used to make water, its properties are very unstable and it is easy to fail and deteriorate after long storage time. Phosphate or polyphosphate is usually added to improve water retention, viscoelasticity, acid-base buffering and metal barrier ability.
Mooncakes made of boiling water containing potassium carbonate are dark red in color and bright in color, which makes people have an appetite. This is the main difference between using water and using sodium carbonate alone.
The role of water:
1. Neutralize the acid in the invert syrup to prevent the sour taste of moon cakes from affecting the taste and mouthfeel.
2. Control the oil return speed and adjust the shell hardness.
3, it is to increase the alkalinity of the moon cake skin, which is conducive to the coloring of moon cakes. The higher the alkalinity, the easier it is to color the mooncake skin.
4. It is the neutralization reaction between water and acid that produces a certain amount of carbon dioxide gas, which promotes the moderate expansion of moon cakes and makes the crust of moon cakes more loose and not deformed.
How to mix water? Formulation of water:
1, 50 g of baking soda powder and 0/5 g of water, mix overnight and filter before use.
2. 25 kg of soda ash powder, 20 g of caustic soda, 80 kg of boiled water and 0.9 kg of edible alkali, all of which are mixed well and can be used. If you don't use caustic soda, use 75 kilograms of water. Soda will turn the baked moon cakes red, which can be added when stirring.
About the concentration of water:
Soaking water is not directly related to the return of oil to the crust, but whether the crust returns oil is only related to the sugar used in syrup concentration, including crust, stuffing and oil. When rubbing the skin, be sure to add water according to the formula standard. If there is too much moisture, the color of the finished product will be dark and easy to burn black. It is easy to get moldy after baking, which affects oil return. It is difficult to color the crust when baking with less water. After cooking, milky white spots appeared on the edge of the cake, and there were several small spots. The bottom skin of the cake turns white, and sand holes affect the appearance.
At present, there are many brands of boiling water on the market, and the quality and concentration vary greatly. Before large-scale production and use, manufacturers had better carry out small batch tests until the color of moon cakes reaches satisfactory results. At the same time, because there are metal ions in the water, it is easy to produce white calcium carbonate precipitation. It's best to heat it before using it, and then worry about it, and remove impurities such as sediment, so the use effect will be better.
In addition, the concentration of water is also very important. Low boiling water concentration leads to large boiling water, which will reduce the amount of syrup in the dough, and the moon cake dough will be "stiff", and the product is not easy to return to oil, soften and deform. If the concentration of water is too high, the surface color of moon cakes will be heavy, the alkalinity will increase and the taste will become worse.
Generally, the concentration of water is 30~35 Baume degree (oBé) or the alkalinity is about 60 degrees, and the relative density is 1.2~ 1.33. Among them, alkalinity refers to the amount of substance (H+) needed to neutralize the alkaline substance in 100g sample, and n(H+) is a numerical value in millimoles; The unit is mol/kg, and the symbol is SI. In practical use, the alkalinity of water is measured by alkalinity meter.