Franz Karl Achard discovered the industrial process to produce table sugar from beets

Franz Karl Achard – discoverer of extraction of sugar from sugar beets

Article on Franz Karl Achard

Biography & Contributions

Franz Karl Achard was a German (Prussian) chemist, physicist and biologist born on April 20, 1753 – died on April 20, 1821. Achard was notable chemist in the sugar extraction process.

Achard revived the discovery by Marggraf in 1747 that sugar beets contained sugar, and devised a process to produce sugar from sugar beets. In 1794, Achard also built an optical telegraph.

Beet Sugar Production Process

Sugar beet is a plant whose root contains a high concentration of sucrose. It is grown commercially for sugar production. The root of the beet contains 75% water, about 20% sugar and 5% pulp. The pulp, insoluble in water and mainly composed of cellulose, hemicellulose, lignin, and pectin, is used in animal feed.

Chemically, sugar is the substance sucrose, which can be hydrolyzed in acidic solution to form the monosaccharides glucose and fructose as follows.

Sucrose + H2O → glucose + fructose

Sucrose may be readily converted by acid or enzymatic hydrolysis into a mixture of the two simpler sugars, glucose and fructose, each with the formula C6H12O6.

Process involved in beet sugar production

  • Harvesting
  • Extraction
  • Pressing
  • Carbonatation
  • Evaporation
  • Crystallization

Chemical processes involved in beet sugar production


Carbonatation is a procedure which removes impurities from raw juice before it undergoes crystallization. First, the juice is mixed with hot milk of lime. Carbonatation process precipitates a number of impurities, including multivalent anions such as sulfate, phosphate, citrate and oxalate, which precipitate as their calcium salts and large organic molecules such as proteins, saponins and pectins, which aggregate in the presence of multivalent cations. In addition, the alkaline conditions convert the simple sugars, glucose and fructose, along with the amino acid glutamine, to chemically stable carboxylic acids.Carbon dioxide is bubbled through the alkaline sugar solution, precipitating the lime as calcium carbonate (chalk). The chalk particles entrap some impurities and absorb others. A final addition of more carbon dioxide precipitates more calcium from solution.

Ca(OH)2 + CO2 → CaCO3 + H2O

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