Beverages and drinking water

Regulatory compliance

Standards

The scope and frequency of drinking water and beverage analyses are regulated in most countries. Besides microbiological analysis and sensory testing, compliance with limit values for impurities is most crucial. Water and beverages are our business. We offer you a multitude of methods and instruments for standard-compliant analysis.

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Chromium(VI): New limit value

Potassium chromate sample
New limit value for chromium(VI) in line with EPA 218.7

California imposes a 10 µg/L limit value for chromate in drinking water. You can determine Cr(VI) by ion chromatography according to EPA method 218.7.

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pH measurement in beverages

The pH value is an important parameter for the quality control of beverages.

It has a significant effect on the digestibility, flavor, and stability of any beverage. The pH value influences color/hue, flavor, redox potential, the ratio between free and bound SO2 in wine, the formation or prevention of iron phosphate turbidity, to name just a few. Moreover, it controls enzyme activity during alcoholic fermentation, which is why it must be checked regularly.

The requirements for the pH electrode used to perform measurements are as diverse as the range of beverages to be analyzed. The selection of a diaphragm suitable for the beverage sample is particularly important, since the sample can quickly block the electrolyte bridge if an unsuitable diaphragm is used, leading to inaccurate results.

Related products and additional information

iUnitrode

The Unitrode – the ideal electrode for beverages in general, e.g., for wine (AOAC 960.19), beer (AOAC 945.10), and spirits. The fixed ground-joint diaphragm prevents contamination.

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iAquatrode

The Aquatrode Plus is the perfect electrode for drinking water analysis. It yields precise results and offers rapid response times even in poorly buffered solutions. Thanks to the fixed ground-joint diaphragm, this electrode is insensitive to contamination.

> Learn more about Aquatrode Plus

Alpha acids in hops according to EBC 7.4

Typical titration curve for hops analysis

Hops play an important role in the brewing process, as they have a critical effect on the flavor, bitterness, and shelf life of beer. The alpha acids in the hops are crucial for the bitterness of the beer.

To achieve the required bitterness at the end of the brewing process, the quantity of hops added must be dosed precisely. Depending on the type of beer, different varieties of hops are used, each with a different alpha acids content. According to the European Brewery Convention (EBC 7.4), the content of alpha acids is determined by conductometric titration with lead acetate solution. This method can be used for all hop products, e.g., hop umbels, pellets, or extracts.

The image on the left shows a typical titration curve for alpha acids in hop products.

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Vitamin C determination by titration (AOAC 967.21), ion chromatography, or polarography

Fruit juices

In addition to occurring naturally in fruits and vegetables, ascorbic acid (vitamin C) is used as an antioxidant in foods and drinks.

Within the European Union, Vitamin C is designated with the E numbers E300–E305. Ascorbic acid and its salts and esters can be determined by titration according to AOAC 967.21. Ion chromatography is another valid option; in particular, when other acids such as acetic or citric acid are involved. Alternatively, vitamin C can be analyzed by polarography with high sensitivity, for which ascorbic acid is oxidized to form dehydroascorbic acid.

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Laboratory automation in beverage analysis with MATi 1

Metrohm Automated Titration 1 system

Comprehensive water analysis includes the determination of various sum parameters (e.g., conductivity, pH value, titratable acidity, alkalinity, hardness) and several individual substances (e.g., chloride). Frequently, these parameters – even in case of a high sample throughput – are sequentially determined on different instruments. This is very time-consuming and requires repetitive sample preparation and expensive laboratory space.

Why not save time and benefit from synergy effects by combining Metrohm devices in a single system that carries out all the mentioned analyses and sample preparations in a single run? Results are centrally recorded and administered in the user-friendly tiamo database.

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Ion chromatography (IC) in beverage and water analysis

Ion chromatography (IC) is a standard method for drinking water and beverage analysis. Numerous main ingredients, components affecting taste and health and traces of contaminants can be reliably and precisely determined with IC.

IC system and laptop with MagIC Net and operator

Multicomponent determinations in a single analysis

In addition to anions and cations, also carbohydrates, organic acids, and polar substances can be quantified in a variety of beverages.

The advantage of IC is that parallel determinations of chemically similar substances can be carried out in a single analysis. Furthermore, the concentration of the analytes can vary from the ng/L up to the percentage range. All Metrohm IC instruments and the MagIC Net chromatography software are of course compliant with FDA standards.

Soliprep system for IC

Save time and costs through automated sample preparation

As in titration, sample preparation and automation have an important role to play in ion chromatography.

Unique inline methods permit the integration and complete automation of sample preparation into the analytical process. This increases safety, reduces the number of manually performed steps, improves reproducibility, and guarantees the traceability of the entire analysis.

> Learn more about Metrohm Inline Sample Preparation (MISP)

Bromate in water according to EPA 300.1, 317, and 326

Water Bromate
Carcinogenic bromate from ozonization

Carcinogenic bromate forms during the ozonization of drinking water. Several international standards stipulate detection limits and test methods.

Great choice of approved detection techniques

Depending on the required detection limit, different detection methods can be used. Conductivity detection with chemical suppression allows the determination of bromate in the lower μg/L range. In the ng/L range, bromate can be detected by IC/MS coupling or post-column derivatization with potassium iodide and subsequent UV detection.

Carbohydrate and sweetener analysis

Soft drinks

How sweet is sweet? This is not an easy question to answer for some beverages. To get the right answer, you first have to know the carbohydrate composition. In addition, the answer requires that the content of sugar alcohols and sweeteners is known.

Ion chromatography uses isocratic elution and pulsed amperometric detection. Beverages generally only require minimal sample preparation such as dilution or filtration, if any.

We have compiled a table listing a wide array of components that can be reliably analyzed in various beverage matrices using ion chromatography and pulsed amperometric detection (PAD). The table also shows the required sample preparation.

> See the table

Identification of structurally similar sugars using handheld Raman spectroscopy

Sugars by Raman spectroscopy

Our handheld Raman spectrometers are ideally suited for fast identification of sugars in beverages.

The following sugars can be identified in beverages within a few seconds and without any sample preparation: D-galactose, D-glucose, D-maltose, D-mannose, D-sorbitol, fructose, sucrose, and inositol. Raman spectroscopy is the ideal method when you need a reliable analysis method and when speed matters.

> Read more about the identification of structurally similar sugars using handheld Raman spectroscopy

Voltammetry in beverage analysis

Water bottles with screw cap

Transition metals in water in accordance with DIN 38406, Part 16

Drinking water has to be tested regularly to determine levels of zinc, cadmium, lead, copper, thallium, nickel, and cobalt. DIN 38406, Part 16 describes the method for determining levels of these ions in different types of water. Determination of transition metals in drinking water is described in the Application Notes below.

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Further applications

Beer and hops

Alkalinity and hardness in beer production

Alkalinity, pH value, and hardness play a crucial role in various steps during the brewing process. Out-of-spec values impair the extraction of starches and the taste of the beer (owing to excess tannin extraction). Close monitoring of the process and make-up water is therefore required. Download this Application Note and learn more about online monitoring of these parameters in the brewing process with Metrohm process analyzers.

Go to the Application Note
PGSTAT 204

Quality control of food & beverage packaging

Packaging aims at preserving food against spoilage and contamination. Moreover, packaging extends shelf life and simplifies handling on the one hand, and provides protection and important consumer information on the other. Due to the danger of compound migration from the packaging into the food, so-called food contact substances (FCS) are subject to FDA approval in the US. Metals are ideally suited for packaging materials because they can be coated with different passivating food-grade layers. Impedance spectroscopy is a viable means to monitor the integrity of the sealing layers.

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Electrochemistry in quality control of food and beverage packaging