This method describes how to determine the electrical conductivity of water using a conductivity meter.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
The electrical conductivity of a water sample is regarded as a sum parameter of all of the ions dissolved in the water sample. The electrical conductivity is determined by the ion concentration and the types of ions as well as the temperature and the viscosity of the solution. Due to dissociation of the water molecules themselves, water containing no dissolved extraneous ions possesses an extremely low electrical conductivity of ≤1 µS/cm-1. Drinking water often exhibits conductivity between 100 and 1000 µS/cm-1 (limit threshold according to the Trinkwasserverordnung – TrinkwV (the regulations governing drinking water in Germany): 2500 µS/cm-1 at 25 °C). By comparison, rainwater exhibits a value for electrical conductivity between 30 and 60 µS/cm-1, while that of sea water is commonly 42,000 µS/cm-1.
Prior to storage, the moisture content of barley must be determined.
Measurement of the electrical resistance in the ground and pressed sample
Determination of the dissolved nitrogen (N2) content using heat conductivity in carbonated and non-carbonated beverages that have been nitrogenated
This analysis is suitable for determining the concentration of dissolved nitrogen (N2) in carbonated and non-carbonated beverages that have been nitrogenated.
Dissolved nitrogen in a liquid medium is measured using the same procedure as the CO2 determination, i.e., using heat conductivity.
CO2 is employed as a purge gas in the beverage industry. Therefore, in order to measure nitrogen, the change in thermal activity and CO2 and N2 is used. The thermal conductivity is determined in a small measurement chamber, which in turn is separated from the material being measured by a semipermeable membrane. Diffusion through the membrane changes the thermal conductivity in the measurement chamber.
The gas volume in the measurement chamber is fully replaced in cycles of 10–20 s. The changes in thermal conductivity over time are a measure of the diffusion of N2 through the membrane, which allows the concentration in the medium to be calculated, taking temperature into account.
The calculation for the concentration of N2 is achieved using the change in thermal conductivity in the measurement chamber, also taking the temperature into account.
Since the thermal conductivity of oxygen is similar to that of nitrogen, a second channel may need to be used to compensate for any oxygen in the medium [1].
Determination of the concentration of dissolved carbon dioxide in carbonated beverages in tanks, lines, bottles and cans by means of thermal conductivity
This analysis is suitable for dissolved carbon dioxide in carbonated beverages in concentrations ranging from 0–6.9 g/l.
The thermal conductivity is measured in a small chamber, which is in turn separated using a semi-permeable membrane from the medium being measured. The diffusion through the membrane alters the thermal conductivity in the measurement chamber. The gas volume in the measurement chamber is completely replaced in 10–20 s cycles. The changes in the thermal conductivity over time are a function of the quantity of CO2 diffusing across the membrane. Using this value and taking into account the temperature, the concentration in the medium being measured can be calculated. Other dissolved gases, such as nitrogen and oxygen, do not affect the result of the measurement, since either nitrogen or air is used to replace the gas in the measurement chamber [1].
All alkaline or acidic cleaning solutions.
The main components of alkaline and acidic detergent solutions are strong electrolytes with a high degree of dissociation. If an electric field is applied in an aqueous system, the ions take over the current transport. This depends, among other things, on the concentration of the electrolyte. By measuring a defined value - the so-called specific conductivity - a linear dependency is given in the concentration range commonly used in cleaning practice and the concentration can be easily determined. The specific conductivity is specified in the unit Siemens or millisiemens per centimeter (S/cm; mS/cm).
Determination of the concentration of active ingredients in alkaline cleaners.
All alkaline cleaning solutions.
Alkaline cleaning solutions, especially for automatic bottle cleaning, consist of sodium hydroxide and so-called active ingredient concentrates. Concentration losses caused by carryover or carbonization can be determined by determining the alkaline component in accordance with
T-740.01.041 Electrolytic conductivity of acidic and alkaline cleaning agents
T-741.02.032 Alkaline cleaning agents - sodium hydroxide only
T-741.03.032 Alkaline cleaning agents containing carbonate - sodium hydroxide and soda
T-741.04.023 Alkaline cleaning agents containing carbonate in the presence of phosphates and soiling - sodium hydroxide and soda
T-741.05.032 Alkaline cleaning agents containing aluminum - sodium hydroxide, aluminum
T-741.06.032 Alkaline cleaning agents containing aluminum - sodium hydroxide, aluminum, soda
can be controlled. However, the active ingredient concentrates are only recorded if it is ensured that the required concentration of the desired active ingredient has been added or dosed using appropriate dosing equipment (proportional dosing). If this is not the case, i.e. if the active ingredient concentrates are prepared and dosed manually, a separate check of the active ingredient concentration is advisable. The determination methods are very different and are specific to a particular active ingredient concentrate*. The method should be requested from the manufacturer.
* e.g. P 3-stabilon; Henkel Hygiene GmbH, D-40554 Düsseldorf, https://www.henkel.de/