74 | Glass Manufacturing Methods, Forming Methods, Processing Methods 12

Hello everyone🎵Until last week, I was on a business trip across the American continent, from New York to Chicago, Denver, and then to Los Angeles, spanning from the East Coast to the West Coast. I visited various places to introduce the sake-specific glasses produced by Kimoto Glass, and to present a new lifestyle of cuisine, sake, and glasses, called "Tripling." I explained this to many sake retailers, restaurants, and sushi restaurants in each area.

Just as there are wine glasses for wine, it's natural that there should be sake glasses for sake. Many people gave me encouraging words. Also, there was strong agreement on the "Tripling" style, where sake breweries, restaurants, and glass manufacturers work as a team to delight customers. Thank you very much.

Now, back to the main topic (laughs).

The glass manufacturing process is as follows: ① Raw material mixing, ② Melting, ③ Forming, ④ Annealing, ⑤ Finishing and inspection, ⑥ Packaging and shipping. We've discussed ① and ②. For forming (③), we talked about free-blowing and mold-blowing methods.

Most of Kimoto Glass's glasses are formed by mold-blowing. I'd like to share a bit more about the actual on-site process.

The surface of a glass is smooth, right? Why is that? If you blow molten glass into a mold, wrinkles can form on the surface, or the glass might stick to the mold. Yet, it always comes out transparent and smooth.

Actually, a mixture of rosin and cork is applied to the inside of the mold. Before blowing molten glass into the mold with a pipe, water is sprayed onto the mold like a shower. One purpose is to cool the mold, but also, the water saturates the rosin and cork mixture. The moment the molten glass is blown in, the water turns into steam, creating a gap between the mold and the blown glass. Within this gap, the glass floats (at a thickness of micron units) as it is blown, resulting in a transparent and smooth glass surface.

Although glasses are created by blowing into molds, there are two main types of molds: "nuki-gata" (pull-out mold) and "wari-gata" (split mold). A "nuki-gata" is, as the name suggests, a mold from which the blown glass can be pulled out directly. Glasses with a somewhat tapered, conical shape at the bottom are made with "nuki-gata." A "wari-gata" is made by combining two or more molds, with a movable joint that allows the mold to open and close for blowing the glass. Both types of molds, as mentioned above, are finished by applying a mixture of rosin and cork. The specific recipe for this mixture is a closely guarded secret at each factory.