Could you roast coffee in an industrial glass kiln and it be drinkable?

A strange question and purely hypothetical. This came about with a discussion with one of my friends who is a glass maker at university.

My first thoughts was that you could not control the temperature enough, however he did state that with glass making, the art is in how fast you can heat and cool down the kiln. So in effect, I don't think the temperature control would be an issue. I feel my issues are:

  1. Rotating of the coffee during the roasting (as it would not be in a drum). It's possible to "spin" glass in this way.
  2. Post roast cooling, would there be a way you could make a makeshift cooling bed that would be somewhat effective.

Drinkable - I guess this depends on personal taste, so for the sake of this exercise I will state that drinkable as the quality of instant coffee. So something you would drink to be polite but not find any pleasure in.

  • I would live to hear if you decide to run a test. Especially what happens at the "first crack" stage. Coffee popcorn, anyone? Ig Nobel Price looming in the shadows ;-)
    – Stephie
    Commented Feb 12, 2016 at 13:56
  • I'm applying peer pressure now :) Commented Feb 12, 2016 at 14:11
  • I'm going to assume Consume Coffee is male, because this is so much a guy idea. Reminds me of - davebarry.com/misccol/charcoal.htm :D Commented Sep 7, 2016 at 18:28

1 Answer 1


If you can run the kiln at sufficiently low temperatures and have a solution for stirring the beans, yes you could roast coffee beans.

"Drinkable" on the other hand is a hard to quantify term.

Ideally, you would roast the raw beans slowy until 200 - 230 C over a time window of 15 - 25 minutes, depending on desired darkness and roast type. This allows for a long and slow Maillard reaction and reduces the content of chlorogenic acid.
Your extremely hot kiln ("cold" glass techniques use temperatures over 800C!) woud be even harsher than industrial roasters with their "90 seconds at 400 C" method. No time for a good Maillard reaction and reduction of chlorogenic acid.

So while you probably can roast (= darken) the beans in a kiln if you are really quick, the results would lack the aromatic profile desired in good quality roasts and the probability of having just a "burnt and sour" brew is extremely high.

  • Good answer! I just quantified "Drinkable" for the sake of this question. Commented Feb 12, 2016 at 13:48
  • 1
    I'm tempted to say "not drinkable" according to the definition above if the rosting process is hotter and faster than (cheap) industrial "quick and hot" roasting for the reasons given in the answer.
    – Stephie
    Commented Feb 12, 2016 at 13:51

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