Potassium Metabisulfite, also known as Pyrosulfurous Acid, Dipotassium Salt, Dipotassium Disulfate, and Potassium Pyrosulfate, has the chemical formula K2S2O5 or K2O5S2. It appears as a white granular or powdery solid with a sharp rotten-egg-like (Sulfur Dioxide) odor. It is soluble in Water and insoluble in Ethanol at ambient conditions. Chemically pure or Laboratory reagents are the two terms often used to describe Lab Grade chemicals. Lab Grade chemicals do not meet any accepted quality or purity requirements such as the ACS Grade, the USP Grade, and the FCC Grade, despite their acceptable purity. In the United States of America (USA), Lab Alley is selling its high-quality Potassium Metabisulfite, Lab Grade online at laballey.com. Due to its high purity, Potassium Metabisulfite, Lab Grade is highly recommended for labs and commercial applications.
Buy Potassium Metabisulfite At LabAlley.com | For Wine Making | For Mead, Cider & Beer | For Sanitizing, Chlorine Removal & Sterilizing | Lab Grade | "Potassium Pyrosulfite" | White Crystalline Powder | Antimicrobial Preservative & Antioxidant | Chemical Disinfectant For Sanitizing And Sterilizing | Food Preservative | Potassium metabisulfite is used as an antioxidant in beer.
In stronger doses potassium bisulfite works well to sanitize your equipment, with no negative consequences. Make a solution of 8 teaspoons dry measure of potassium metabisulfite added to 1 gallon (4 liters) of water, and then rinse your equipment in this solution for about 5 minutes to sanitize, and let drip dry. Read more here.
Preservatives permitted in livestock foods are sodium acetate, natamycin, pimamycin, nisin, nitrites (potassium nitrite and sodium nitrite), nitrates (potassium nitrate and sodium nitrate), sorbates (sorbic acid, sodium sorbate, potassium sorbate, and calcium sorbate), and sulphites (sulfur dioxide, sodium sulfite, sodium bisulfite, sodium metabisulfite, potassium metabisulfite, potassium sulfite, and potassium bisulfite) (Food and Drug Administration, 2016).
- Potassium Metabisulfite Formula: K2S2O5
- Potassium Metabisulfite CAS Registry Number: 16731-55-8
- Potassium Metabisulfite Molar Mass: 222.32 g/mol
- Other anions: Potassium bisulfite; Potassium sulfite
- Other cations: Sodium metabisulfite
- Potassium Metabisulfite Solubility: Insoluble in Ethanol
- Main hazards: Irritant, asthma risk
- Potassium Metabisulfite PubChem CID: 28019
- Potassium Metabisulfite Safety And Hazards
- Potassium Metabisulfite ChemSpider ID: 26061
- Potassium Metabisulfite Properties, Structure, Spectra, Vendors, Articles, Links
Potassium metabisulfite, K2S2O5, also known as potassium pyrosulfite, is a white crystalline powder with a pungent odour. It is mainly used as an antioxidant or chemical sterilant. As a disulfite, it is chemically very similar to sodium metabisulfite, with which it is sometimes used interchangeably. Potassium metabisulfite has a monoclinic crystal structure.
Potassium Metabisulfite Uses
It is used as a food additive, also known as E224. It is restricted in use and may cause allergic reactions in some sensitive persons.
Potassium Metabisulfite And Wine
Potassium metabisulfite is a common wine or must additive, in which it forms sulfur dioxide (SO2). Sulfur dioxide is a disinfectant. It also acts as a potent antioxidant, protecting both the color and delicate flavors of wine. A high dose would be 3 grams of potassium metabisulfite per six-gallon bucket of must (yielding roughly 75 ppm of SO2) prior to fermentation; then 6 grams per six-gallon bucket (150 ppm of SO2) at bottling. Some countries regulate the SO2 content of wines. Winemaking equipment is sanitized by spraying with a 1% SO2 (2 tsp potassium metabisulfite per L) solution.
Potassium Metabisulfite And Beer
Potassium metabisulfite is sometimes used in the brewing industry to inhibit the growth of wild bacteria and fungi. This step is called 'stabilizing'. It is also used to neutralize monochloramine from tap water. It is used both by homebrewers and commercial brewers alike. It is not used as much for brewing beer, because the wort is almost always boiled, which kills most microorganisms.
Other Uses Of Potassium Metabisulfite
- Potassium metabisulfite is sometimes added to lemon juice as a preservative.
- Potassium metabisulfite is used in the textile industry for dyeing and cotton printing.
- Potassium metabisulfite is sometimes used to precipitate gold from solution in aqua regia (as an alternative to sodium sulfite).
- It is a component of certain photographic developers and solutions used in photographic fixing.
- It is used as a bleaching agent in the production of coconut cream.
- It is used in some pickles as a preservative.
- It is used in tint etching iron-based metal samples for microstructural analysis.
Potassium Metabisulfite Safety
Potassium metabisulfite can irritate skin, eyes, and respiratory tract.
Potassium metabisulfite appears as a white granular or powdery solid with a sharp odor of sulfur dioxide. Decomposes at 150 to 190°C. Density 2.3 g / cm3. Contact severely irritates skin, eyes, and mucous membranes. Low toxicity. Used as a food preservative and an antioxidant.
Potassium metabisulfite is often called a stabilizer because it serves to prevent spoilage and further fermentation by removing oxygen. However, this serves another purpose it preserves the flavor and color of a wine. Potassium metabisulfite may also be used as a sanitizing agent due to its antioxidant properties.
Potassium sorbate and potassium metabisulfite accomplish different things, and can be used together to both stop fermentation and prevent renewed fermentation.
Potassium metabisulfite is the active ingredient in campden tablets. One campden tablet is added per gallon. So, 5 campden tablets for a 5 gallon batch. By using sulfites, the mead will have the stability it needs to protect itself from infection, even over long aging times. Read more here.
Potassium metabisulfite is a food preservative, which preserves the natural color of food and protects food against bacteria. Winemakers also use potassium metabisulphite to preserve bottled wines. Read more here.
Campden tablets (potassium or sodium metabisulfite) are a sulfur-based product that is used primarily to sterilize wine, cider and in beer making to kill bacteria and to inhibit the growth of most wild yeast: this product is also used to eliminate both free chlorine and the more stable form, chloramine, from water solutions (e.g., drinking water from municipal sources). Campden tablets allow the amateur brewer to easily measure small quantities of sodium metabisulfite, so it can be used to protect against wild yeast and bacteria without affecting flavour. Untreated cider must frequently suffers from acetobacter contamination causing vinegar spoilage. Yeasts are resistant to the tablets but the acetobacter are easily killed off, hence treatment is important in cider production.
Typical use is one crushed Campden tablet per US gallon (3.8 L) of must or wort. This dosage contributes 67 ppm sulfur dioxide to the wort but the level of active sulfur dioxide diminishes rapidly as it reacts with chlorine and chloramine, and with aldehydes (particularly in wine). Therefore, the concentration of free sulfur dioxide is greatly diminished by the time the beer or wine is consumed. However, when used only for the purpose of dechlorinating tap water before brewing, one tablet will effectively treat 20 US gallons (75 L) of water.
Campden tablets are also used as an anti-oxidizing agent when transferring wine between containers. The sodium metabisulfite in the Campden tablets will trap oxygen that enters the wine, preventing it from doing any harm.
It is a common misconception that Campden tablets can be used to halt the ferment process in wine before all the available sugars are converted by the yeast, hence controlling the amount of residual sweetness in the final product. This however is not true. In order to halt fermentation, enough Campden tablets would have to be added to render the wine undrinkable. Alternatively, when used in conjunction with potassium sorbate, the yeast population will be greatly reduced and prevented from reproducing. Without the addition of potassium sorbate the yeast population will only be stunned and eventually repopulate if provided with enough fermentable sugars.
Campden tablets typically contain 0.44 g each of sodium metabisulfite (plus filler) and 8 of these are equivalent to one half level teaspoon (2.5 mL) of sodium metabisulfite. Other Campden tablet formulations use potassium matabisulfite. Each is also referred to interchangeably as—sulfites, and the 'bi' can be found as 'di'. In terms of usage, sodium thiosulfate is a closely related compound.
The name Campden tablet comes from the town of Chipping Campden in Gloucestershire, England, where the original solution was developed in the 1920s by the Fruit and Vegetable Preserving Research Station - now Campden BRI. The idea was then taken up by the Boots Co., who developed the tablet.
Campden tablets are also useful in decontamination and neutralization after exposure to tear gas.
The molar mass (commonly called molecular weight or MW) of potassium metabisulfite is 222 g/mol, while the molecular weight of sodium metabisulfite is 190 g/mol. Read more here.
- Sanitizing agent
- Disinfecting agent
- Textile industry
- Cotton printing
- Purification of gold
Please contact us to request a Safety Data Sheet (SDS) and Certificate of Analysis (COA) for Potassium Metabisulfite Lab.