Midwest Hop and Beer Analysis, LLC

Providing a quality chemical analysis service for regional hop growers and craft beer brewers in the Midwest.



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Our ASBC Hop Testing Methods


Corporate Member:
Link to American Society of 
                  Brewing Chemists

Midwest Hop and Beer Analysis, LLC, is proud to be a Corporate Member of the American Society of Brewing Chemists (ASBC). We are committed to following the testing protocols developed by both the (ASBC) and the European Brewing Convention (EBC). Both organizations cooperate to establish National and International standards in the Brewing Industry.

Top Menu ASBC Methods Moisture by Distillation Moisture by Air-Cabinet Alpha/Beta Acids Hop Storage Index Essential Oils


Moisture Content by Distillation

ASBC Hop-4A (Distillation Method)
Pricing

Distillation is recognized by the ASBC as the most accurate method of determining the actual moisture content. However, it is a time consuming process that involves boiling a precisely measured sample of hops in an organic solvent like purified methylcyclohexane. The water and solvent vapors are cooled, returning them to their liquid form. As they trickle back toward the boiling-flask, the moisture is retained in a catch-tube. The system requires careful calibration, but can return consistent and reliable results.
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Top Menu ASBC Methods Moisture by Distillation Moisture by Air-Cabinet Alpha/Beta Acids Hop Storage Index Essential Oils


Moisture Content by Forced-Air Drying Cabinet

ASBC Hops-4C (Routine Air Oven Method)
Pricing

Oven drying is a more practical approach in which a moisture-containing sample is carefully weighed and then dried in an oven with a forced air flow and carefully regulated temperatures. The sample is reweighed after drying and the lost mass is assumed to be due to the evaporated moisture. However, typical oven temperatures (over 170 degrees F) drive off some of the essential oils, as well as the moisture, leading to inescapable errors. We use a low temperature (below 110 degrees F) dehydrating system, designed specifically for this one purpose, and calibrated by referencing results from distillation tests.
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Alpha Acids and Beta Acids Content by UV Spectroscopy

ASBC Hops-6A (by solvent extraction and spectrophotometry)
Pricing

This method accurately reports the total amount of the α-acids and β-acids present, but does not provide specific information on the identities or relative amounts of the individual acids (e.g., humulone, cohumulone and adhumulone). We feel that knowledge of the amounts of specific α-acids in a sample are of less importance to the brewer than the actual perceived bitterness. If you are at all concerned about the bitterness characteristics of your hops, then, by all means, make a tea of them and taste it!

This is the original ASBC solvent extraction method established as the standard in 1970 and revised in 2008. The hops (wet or dry, whole or processed) to be tested are carefully weighed and coarsely ground. An ultra-pure organic solvent (toluene) is added to the sample and agitated to dissolve the alpha- and beta-acids. The solution, now containing a variety of compounds, is separated from the solid hop residue and further treated to prepare it for spectrometry. The final solution, containing the diluted extracts of alpha and beta acids, is placed in a calibrated ultraviolet (UV) spectrophotometer. The amount of UV light absorbed by the solution at three specific wavelengths indicate the amount of alpha acids and beta acids present in the solution. Knowing the weight of the hop sample and the volumes of the various solvents added allows one to determine the amount of the bittering acids in the original sample.
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Hop Storage Index (HSI)

ASBC Hops-12 (by solvent extraction and spectrophotometry)
Pricing

This measurement relies on the same solvent extraction and spectrophotometry process used (and described) above, though it depends on a slightly different mathematical analysis. For this reason, the results of the HSI analysis is included as part of the previous test.

As the hops "age" with exposure to time, heat and oxygen, the α-acids are converted into a variety of unflavored and off-flavored compounds, collectively referred to as "oxidized α-acids". As the oxidation takes place, the absorbance of UV light at the wavelength corresponding to the α-acids decreases, while the absorbance at the wavelength corresponding to the oxidized α-acids increases. The ratio of one absorbance value to the other gives a unit-less number known as the Hop Storage Index. HSI values run from a low of about 0.24 to a high of about 2.5. On this scale, lower numbers are "good" and higher numbers are "bad."
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Total Essential Oil Content by Steam Distillation

ASBC Hop-13 (by steam distillation)
Pricing

This method accurately reports the total amount of all essential oils present, but does not provide specific information on the identities or relative amounts of the individual essential oils. We feel that knowledge of the amounts of specific oils in a sample is of less importance to the brewer than the actual perceived aroma and taste. If you are at all concerned about the flavor of your finishing hops, then, by all means, taste them!

A large, carefully weighed sample of hops is placed in a large water-filled vessel and brought to a steady boil. Steam from the boiling water and vapors from the essential oils are cooled in a chilled condensing column and return to their liquid forms. As they trickle back toward the boiling-flask, the liquid essential oils are retained in a syphon-like catch-tube. The system requires careful calibration, but can return consistent and reliable results.
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Top Menu ASBC Methods Moisture by Distillation Moisture by Air-Cabinet Alpha/Beta Acids Hop Storage Index Essential Oils