What’s tempering?

[ad_1]

Tempering is a heat-based process used both in the production of finished metals, alloys and glass, as well as in the production of chocolate. While tempering chocolate is very different from tempering steel or glass, most tempering projects involve heating a substance a second time to create a finished product that is less brittle and more malleable than its previous form.

With steel, the first firing process that creates the hardening often leaves the alloy too brittle for most uses. To transform steel into a more usable form, such as for knife blades, tempering must be done both to relieve some of the internal stresses and for the brittleness caused by the initial heating. Tempering requires heating of the alloy, but to a lesser extent than its original heat treatment. Knowing the correct temperature to temper a steel object depends on its intended use; there are many different grades of character that may be required for different items. However, while reducing brittleness, the process also slightly weakens the steel.

Tempered glass is used in most automobiles, where a stronger glass is needed to withstand the daily stresses of driving. Tempered glass is produced by exposing the glass to a heat process followed by rapid cooling. According to some experts, this increases the strength of the glass enormously, making it much safer for high-stress environments. The rapid cooling process creates extremely weak edges, compared to the sheet’s strong center, which means tempered glass needs to be filed or sanded to create even strength.

Any pastry chef will tell you that tempering is necessary to create the best chocolates. Chocolate is neither glossy nor particularly smooth in its natural state; as the melted chocolate cools and reforms, it creates a crystalline structure that can be manipulated by handling the cooling heat. Untempered chocolate will cool into a grainy block that can be gray, streaky, and brittle to the touch. Keeping the chocolate at a temperate heat until it’s being poured or used will help it cool into a smooth, shiny, malleable shape with a higher melting temperature. Depending on whether you’re using dark, milk, or white chocolate, the temperature needed to create tempered chocolate will vary.

In any form, tempered material changes its appearance and characteristics because the fine structures of the material are altered. Despite this relatively sophisticated concept, the tempering process has been around for centuries longer than the science that describes it. The origin of tempered products in nearly every industry is difficult to trace, but the effectiveness and utility of this unique process continues to influence the manufacture of a variety of products.

[ad_2]