dustin360 wrote:Anyway im curious why you dont think it does well for brew roasts, but it does well for espresso roasts? So the only mod was getting the drum black?

Dustin, good question, and it was Jim that really figured it out for me. It has to do with the higher temperature of the drum and how it impacts the beans. When using lower drum temps, the outside and inside of the bean can develop at relatively similar rates leading to a more even roast. This is particularly important, as Jim mentioned, in both lighter and darker roasts.

When roasting using my method and ending the roast at a typical City/Cupping roast, the outside of the bean would be perfect yet the inside would be underdeveloped. The same holds true for darker Vienna of FC+ roasts. The outside would get there faster than the inside.

The nice thing about using this method for espresso is that if you are roasting between these two extremes, you can get a wider range of taste notes from a bean. You might have the cinnamon or spice from the darker range mixed in with some of the fruit or caramel from something lighter. It adds another dimension to the flavor profile.

One important element I forgot to mention is that turning the fan completely off and closing the chute is critical to getting an even bean development. I've tried different methods and have found that if I keep the fan off to 240 BT, the beans end up being roughly even at finish. Comparing my results to Jim's verified this.

I don't think the relevant point is whether the drum is hotter when it's black ( it is) but more importantly, that it conducts heat much faster and more efficently.

Cool, thanks for the explanation. So your only roasting for espresso then, and find it hard to do lighter brew roasts?

And I bring up a hotter drum, because tipping is mainly caused by conduction. So a hotter drum could equal more tipping(i said could, not does). But once again maybe this is negated with larger loads because there is less bean to drum contact. But maybe im confused again, is there a way the drum could conduct heat better without it being hotter than before?

My theory ( and I could be wrong) is that the MET that is very high, wont have as much an impact on the roast when the outside of the drum is shiny metal, reflecting a lot of the heat versus the black drum surface that quickly transfers it in. So MET and tipping aren't as relevant to me unless I'm not closely watching all the parameters and making sure the BT isn't flying too high late in the roast. I can cut the heat much easier and coast in, without tipping now.

I just finished a 50/50 blend of a Guate and a Brazil that needed a lower charge temp and a more delicate but short roast. I noticed tipping only on two beans in the whole batch, and they were odd shells of beans, mis-formed and not normal.

I ran a batch of Ethiopian a bit hotter on the initial charge, and ran it longer, without ending up with an espresso roast, just prior to the Guate/Brazil batch.