I have a Gene Cafe that I have been using at home for some time. On inital reading of the directions, it recommends washing the roasting chamber:

Oils and residual debris remaining from the roasting process will build up and adversely affect the taste of future batches. Clean the chamber using a dish washing brush, sponge and dish washing liquid. Dry the chamber completely before storing it away.

However, I know that there is a lot of juju surrounding the seasoning of commercial roasters. I've wiped the inside out on a couple of occasions with a cloth when I've accidently over roasted and ended up with a lot of oil in there. If I leave a lot of oil in the chamber, it seems to shorten the end roast times of future batches (they move through the later stages of roasting too quickly to be well controlled).

So basically, to clean, or not to clean?

1 Answer 1


The roasting chamber of your Gene Cafe is made of Pyrex (heat-resistant tempered glass), and leaving the old oils to accumulate and burn will cause the the inside of the drum to turn black. The darker material will likely change your roasting time, and the fouled glass will not allow you to monitor your roasts. Glass does not need "seasoning", so it should be cleaned regularly per the manufacturer's recommendations.

Seasoning is typically a way to create a stick-resistant coating on a porous metal surface (like cast iron or carbon steel). When a thin layer of fat or oil is heated on these surfaces, it forms a polymer which provides rust protection and creates a non-stick surface that will keep whatever you are cooking/roasting from reacting with the cooking surface (the juju you mentioned above).

If the roasting chamber were made of cast iron or carbon steel, seasoning would be recommended. But neither glass nor stainless steel need seasoning, and you're just changing the built-in characteristics of your roaster.

To keep your roaster in optimal roasting condition, keep your glass roasting chamber clean.

  • Thanks for the response. There is indeed a goodly portion (maybe half the surface area?) of the chamber that is Pyrex. However, there is also a good portion that is metal (both end caps, and the plate in the center. So perhaps I should be scrubbing the Pyrex, but not the metal portions? Just for edification I have been running roughly three batches a week through it for more than six months, haven't ever washed it, and can still see through the glass just fine. Commented Mar 3, 2015 at 16:19
  • @ChrisinAK I could not find a reference, but I very much doubt those metal surfaces are made of carbon steel or cast iron (or they would be rusting). In either case, they do not need seasoning, and I would just follow the manufacturer's recommendations and keep them clean. Commented Mar 3, 2015 at 16:22
  • Thanks, I reread your answer and realized that, but was past the window to edit the comment. Commented Mar 3, 2015 at 16:26

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