As the largest brewery in China, and the 6th largest in the world, Tsingtao aims to produce a consistently high-quality beer. To achieve this, they developed standard operating procedures to identify changes that occur during the brewing process that could affect taste and quality.
Their solution was simple, test beer using a headspace trap and gas chromatograph to analyze its flavor compounds and defects.
The Challenge of Measuring Such a Complex Product
Beer is complicated.
"In addition to monitoring product quality, the instruments are used to quickly determine the root cause of any quality incident that might occur."
The fizzy adult beverage blends hops and malted grains into a highly complex mixture of many compounds, including sugars, proteins, alcohols, esters, acids, ketons, and terpenes. It’s this chemical content that gives beer its flavor. The aroma of beer is largely determined by volatile organic compounds (VOCs), and is also a key factor in measuring the quality of a batch of beer.
Most breweries, including Tsingtao, leave it to human taste testers to sample and smell beer batches to ensure the quality of their product. But Tsingtao supplements its testers with scientific and molecular analysis to provide objective and measurable quality standards.
Tsingtao's Long History in Beer
The company was founded in Hong Kong by German settlers and served its first beer in 1904. Today it’s owned by Asahi Breweries and based in Qingdao, China. Its flagship beer is a standard pilsner but it produces a number of other beer styles for local markets, including a dark beer. Tsingtao first exported its beer in 1954, with it first becoming available for U.S. customers beginning in 1972. Today it is the top consumer product exported from China.
Identifying the Qualities of Good Beer and How They Can Be Measured
Tsingta'’s technical center, the team that is responsible for monitoring product quality, identified two key qualities of the company’s product: 2,3-butanedione and 2-3-pentanedione, vicinal diketones that produce a butter-like flavor and can cause an adverse odor at high levels, and Acetaldehyde, which has the taste and aroma of fresh-cut green apples. Acetaldehyde is reduced to ethanol by yeast during secondary fermentation, but oxidation of the finished beer can reverse this process and convert the ethanol back to acetaldehyde.
A careful balance of these flavors are required to produce Tsingtao’s signature beer, Tsingtao Beer, a well-hopped standard pilsner with 4.7% alcohol-by-volume.
Using Headspace Chromatography to Ensure High Quality
Headspace sampling is a state-of-the-art method for sampling the aroma of beer and other foods. The beer is placed into a vial which is then sealed. The vial is then heated to release the vapor into the headspace (the empty area at the top of the vial). The vapor is then extracted and analyzed using gas chromatography.
At equilibrium, the concentration in the headspace phase is proportional to the original concentration in the sample. The headspace trap technique can enhance detection limits by a factor of 100, ensuring that the sample being measured meets quality standards.
The beer samples are degassed prior to headspace analysis to prevent dissolved carbon dioxide from influencing vial pressure and to minimize disturbances it can cause during chromatography. A sample of beer is then placed into a headspace vial and heated. The chromatograph then measures the vapor, separating all of the components. If the screening tests indicate that the targeted components exist at undesirable levels, more specific analyses can be performed to follow-up.
The Effects of Stringent Testing
Once the final methods were developed, they were rolled out to breweries across China. In addition to monitoring product quality, the instruments are used to quickly determine the root cause of any quality incident that might occur.
For example, a batch of beer products was once found to contain an unusual odor. The whole batch of beer was removed from the product flow and samples were sent to the technology center for analysis.
Scientific analysis is also providing valuable input to the product development process. The technology center runs flavor fingerprint analysis to help determine the differences between Tsingtao beers and other branded products in the market. The results are studied to determine why certain products are preferred by specific groups of consumers and guide new product development. New products developed by the research and development department are tested in the same way.
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