Acid gas and chemical fume control during beer bitterness testing

Home brewers, microbreweries and large-scale production plants often perform quality assurance tests throughout the brewing process to ensure a consistent, exceptional product.

One of the tests in particular determines a beer’s bitterness ratio. Various measurement techniques can be performed to acquire this rating.

The American Society of Brewing Chemists’ (ASBC) Method of Analysis Beer – 23A, is a very common method for performing such test.

The method uses certain chemicals that aid in component separation and extraction.

Chemicals include : 1-Octanol; 2, 2, 4-Trimethylpentane; and 3 N Hydrochloric Acid

Source: WETNEWF.org

Source: WETNEWF.org

According to Method 23A, the steps to determine bitterness ratios are*:

  1. Transfer 10 mL of cold carbonated beer to a 50 mL centrifuge tube. Dip the tip of the pipet into octanol and shake off excess.
  2. Add 1 mL 3N hydrochloric acid and 20 mL spectrographic grade 2,2,4-Trimethylpentane.
  3. Close the centrifuge tube and shake vigorously for 15 minutes.
  4. If the phases do not separate, centrifuge the tube until they do.
  5. While shaking or centrifuging are underway, prepare an isooctane blank by touching a toothpick or micropipette tip which has been dipped in octanol to the inside of a 1 cm quart curvet. Then pipet in 1-3 mL isooctane, depending on how high you must fill cuvets for accurate reading in your spectrophotometer and cap it.
  6. As soon as possible after the completion of shaking or centrifugation, pipet clear isooctane from the centrifuge tube into another 1 cm quartz cuvet and close. The closure prevents evaporation of isooctane, which is beneficial both because the concentration of isohumulone in the cuvet is not increased as octane evaporates, and because the interior of the spectrophotometer is not exposed to hydrocarbon fumes.
  7. Set the photometer to 275 nanometers wavelength, zero the instrument with the blank and read the absorption. Multiply the absorption value by 50.
*As adapted by WETNEWF.org

 

Chemical Fume Exposure

Source: WETNEWF.org

Source: WETNEWF.org

While performing this test, appropriate engineering safety control measures should be used to avoid inhaling gaseous vapor and fume emitted from these chemicals.

The below charts outline the various health and respiratory hazardous as cited in their respective Safety Data Sheets (MSDS).

1-Octanol [CAS #111-87-5]

  • Hazardous in case of inhalation.

  • Do not breathe gas/fumes/vapor/spray.

  • Provide exhaust ventilation or other engineering controls to keep the airborne concentration of vapors below their respective threshold limit value.

Exposure Limits

American Industrial Hygiene Association (AIHA) Workplace Environmental Exposure Limit (WEEL)

50ppm Time Weighted Average

2, 2, 4-Trimethylpentane [CAS #540-84-1]

  • Hazardous in case of inhalation.

  • Do not breathe gas/fumes/vapor/spray.

  • May cause irritation to the respiratory tract with coughing, wheezing, shortness of breath, and pulmonary edema.

  • Higher levels could cause “chemical pneumonia” and may cause you to pass out and even stop breathing.

  • May affect the brain, behavior/central nervous system and cause narcotic effects at high concentration.

  • The substance may be toxic to kidneys, lungs, liver, central nervous systems.

  • Repeated or prolonged exposure to the substance can produce target organ damage.

  • Provide exhaust ventilation or other engineering controls to keep the airborne concentrations of vapors below their respective threshold limit value.

Exposure Limits

American Conference of Industrial Hygienists (ACGIH) Threshold Limit Value (TLV)

300ppm Time Weighted Average

3 N Hydrochloric Acid [CAS #7647-01-0]

  • Do not breathe gas/fumes/vapor/spray.

  • Inhalation of hydrochloric acid mist or fumes produces nose, throat, laryngeal, bronchial irritation and possible burns, pain and inflammation, coughing, sneezing, choking sensation, hoarseness, laryngeal spasms, upper respiratory tract edema, chest pains, as well as headache and palpitation.

  • Liquid or spray mist may produce tissue damage particularly on mucous membranes of eyes, mouth and respiratory tract.

  • Inhalation of the spray mist may produce severe irritation of respiratory tract, characterized by coughing, choking or shortness of breath.

  • Repeated or prolonged exposure to the substance can produce target organ damage.

  • Provide exhaust ventilation or other engineering controls to keep the airborne concentrations of vapors below their respective threshold limit value.

Exposure Limits

OSHA Permissible Exposure Limit (PEL)ACGIH Threshold Limit Value (TLV)

National Institute for Occupational Safety and Health (NIOSH)

7mg/m3, Ceiling

OSHA Immediately Dangerous to Life or Health

50 ppm

Engineering Safety Controls

SAS Model 200 Winged SentryFor this type of application, a bench top fume extractor with a 50/50 activated carbon/acid gas blended filter is recommended.

Our Model 200 Winged Sentry has a unique design allowing an adjustable work area through the use of “wing flaps”.

The operator can place these wings in the most effective position for fume capture, or they can be positioned flat against the sides of the unit to conserve space.

SAS Model 200 Winged Sentry w/ LidIn addition, an optional clear lid can be added atop the wings to create even greater fume containment.

A specially-blended 50% activated carbon and 50% acid gas filter works to adsorb chemical and acid gas molecules within the porous structure of the granules so that cleaner air is recirculated back into the work space.

By utilizing the Winged Sentry unit, harmful acid gas molecules generated during the pipetting and transferring of chemicals, and the opening and capping of test tubes, can be captured and filtered before entering the operator’s breathing zone.

Contact Sentry Air

For more information about chemical fume control or to receive a free quote on our fume extraction systems, contact Sentry Air Systems at 800.799.4609, email sales@sentryair.com, visit our website or fill out the feedback form below.