What the sugar meter does and how to use it
Some craft beer enthusiasts come to consult how to use the sugar meter, and even some craft beer lovers who have already made commercial brews have little knowledge about measuring sugar content. Accurate measurement of sugar content is an important data reference for subsequent precise control of each node in the brewing process. In today's content, we will introduce the instruments and procedures for measuring sugar content.
measuring instrument
Common instruments for measuring sugar content include sugar content meters, hydrometers, hand-held refractometers, etc.
If we want to understand and use these instruments, we need to understand the relationship between sugar content and wort concentration.
Wort contains a lot of sugar, protein and various vitamins, but sugar accounts for the majority in wort, so the concentration of wort is about equal to the sugar content in wort. This is what I often refer to as the original wort concentration and we all think it is the sugar content of the original wort.
Principle of hydrometer/sugar meter
The principle of the hydrometer and the sugar meter is the same, and the specific gravity of a specific solution is measured by the height it floats in the solution, but the units of the sugar meter and the hydrometer are different.
The estimation formula of the unit: [(specific gravity-1)*1000]/4=sugar content
For example, the specific gravity of wort is 1.040. According to the conversion formula, the sugar content is approximately equal to 10p. The relative density is measured, which is the density of the solution relative to water. The specific gravity of water is 1.000. The reading refers to the standard temperature (20 degrees Celsius). Density is temperature dependent, so the hydrometer reading should be corrected to the specific gravity at standard temperature.
Use of hydrometer/sugar meter
Since the use of the two is very similar, we use the sugar meter as an example. According to the principle of the sugar meter, we know that the reading of the sugar meter needs to be measured at a standard temperature, so we can use a sugar meter with an attached temperature, so that if it is not at 20°C, the temperature can be directly compensated.
The temperature-attached sugar meter is a float meter, which is made according to the principle of liquid density meter. The lower the relative density of the liquid, the deeper the density meter sinks. The slender rod of the sugar meter is engraved with a mass percentage scale.
(1) Cleaning of the sugar meter The sugar meter should be cleaned with the wort to be tested, and cannot be washed with water or other liquids, so as to avoid changes in the concentration of the wort and obtain accurate measurement results as much as possible. In the same way, in order to make the wort temperature in the measuring cylinder evenly mixed, the spiral stirring rod used should also be washed with the wort to be measured.
(2) Cooling of wort Take a small amount of wort and put it in a metal cylinder. There is a metal cooling jacket outside the metal cylinder, which can cool the wort to about 20°C, because the sugar meter is calibrated at 20°C. Of course, when cooling, it is necessary to ensure that the wort cannot be diluted, and to avoid the concentration increase caused by the evaporation of water in the wort.
(3) Reading of the sugar content meter Carefully hold the upper end of the sugar content meter, slowly place it on the scale of the estimated value, wait a moment, and after the sugar content meter is stable, read the position of the narrow tube from the convex scale where the wort contacts the sugar content meter display value.
Then check the correction value corresponding to the temperature scale in the lower half of the sugar meter. If the temperature of the measured wort is higher than 20°C, add the correction value to the displayed value of the sugar meter; if it is lower than 20°C, add the displayed value of the sugar meter Subtract the correction value. If the reading of an accuracy meter is 11.6°P, and the correction value under 20°C is 0.2°P, then the concentration of the wort is 11.6-0.2=11.4°P, that is, at 20°C, 100kg of the wort contains 11.4kg leachate.
Note: Although the sugar meter with temperature is equipped with temperature compensation, the temperature compensation requires time, and the temperature should not be too high. It is recommended to control the temperature of the wort at around 20°C when measuring.
At the same time, when measuring the fermentation broth, the carbon dioxide in the fermentation broth must be removed, otherwise it will have a lot of influence on the measurement results.
