10 Mind-Altering Facts About Glassblowing

Part ancient technique, part contemporary craft: Glassblowing is so much more than a cruise ship spectacle to partake in after you pack it in at the lunch buffet. From the stained glass windows at Notre Dame to Murano glass beads, it’s a highly skilled endeavor that’s been honed for centuries in countries all over the world. The best part? It’s still happening right here in your city, and it’s something you can totally learn through hands-on instruction.

If you’ve ever wondered what it’s really like to be on the right end of a blowpipe, or wanted to try your hand at making a new set of wine glasses to impress your friends, we’ve got the scoop on how it’s done (and some fun facts to boot).

1. Nature was the original glassblower. Lightning strikes on beaches produced thin glass rods called fulgurites, and over the centuries volcanic eruptions have fused sand and rocks into obsidian.

2. Phoenician sailors may have accidentally discovered glass. Pliny suggested that they unintentionally produced glass by building fires on blocks of soda on beach sand, though it’s equally likely that glass was discovered by Egyptian or Mesopotamian potters as they fired clay.

3. Syrians were probably the first ones to blow glass in the first century BC. History suggests that they discovered the technique of blowing into a hollow tube to introduce an air bubble into hot glass. The tradition of glassblowing can also be traced back to the Roman Empire.

4. Italian glassblowers were sequestered on Murano in the Middle Ages. It’s rumored that they were removed to the now-famous island to keep their advanced techniques a secret from the rest of the world, and protect the community from fires started by their furnaces.

5. Glass is an amorphous solid, and no, that’s not a contradiction in terms. It’s solid, but it has a molecular structure that’s random, like a liquid. This amorphous molecular structure is what makes it transparent—light waves are able to penetrate it easily.

6. It’s made from high-quality sand, sort of. Glass is cooked up from a purified form of silica mixed with additives like soda and lime that bring down the melting point and increase viscosity. Metal oxides can also be added for color.

7. It is HOT. Glass melts around 2,400 degrees fahrenheit. Glassblowers “cool” the molten mixture to a gentler 2,000 degrees before it’s blown and shaped.

8. The vocabulary is incredible. Experienced glassblowers are called “gaffers,” workshops are called “hot shops,” silica is melted in “crucibles” and shaped on a “maver,” and molten glass is periodically reheated in a furnace called a “glory hole.”

9. It takes a looooong time to cool. Glass needs to be reheated often to maintain its workability throughout the blowing process, but it also has to be cooled carefully in a temperature-controlled chamber called an annealer for hours, or sometimes days. Glass that cools too fast will crystallize, compromising its transparency and making it much more fragile.

10. Free blowing and mold blowing are real techniques, and the most common ones in use today. The names are totally descriptive of the respective processes—free blowing involves forming the glass completely by hand, whereas mold blowing involves blowing glass into a mold in order to give it shape.

Did we sufficiently inspire you to make your own glass objet d’art? Browse all of our glassblowing classes.