why does it seem that pro-roasts last longer than home? - Page 2

[coffee_monkey]

To be honest, I have not quite figure out why a direct flame roasts will last longer than semi-hot air ones.

I do know that, the airflow is different in a perforated drum (direct flame) than a solid drum (semi-hot air). That will have an affect on the heat transfer efficiency. The drum material type, heat source (electric, infrared heater, gas, and charcoal) will also play a role. Maybe that is somewhat like the "pizza oven effect"? Baked goods made in a convection oven, no matter how good it is, will never approach a traditional brick oven.

This presentation by Arno Schwenk has a lot of good information. It's worth sitting thru:
«missing video»

As for what caused the bean to last longer... I have some theories but they are kind of shaky

[another_jim]

I don't think it's true if the airroast is done right; that is, the bean is properly dried, and not overdried, before it hits 300.

Among specialty coffee people; I am in a very small minority on this: my take is that both drum and air roasters are outdated technologies. The big industrial roasters, who need to turn sows ears into purses, have been going through a lot of technologies in the last 40 years, and have settled on convection roasters with mechanical agitation (the closest home set up is an SC/TO, provided the air temp is properly controlled -- i.e. PIDed). This allows both the bean temperature and the oven temperature to be separately profiled. There is simply no reason to believe that drum roasts are better -- those with unlimited budgets wouldn't dream of using one.

One factor is that pro roasts come in valve bags, while home roasts are mostly stored in mason jars. This, along with less than perfect profiling will make the difference.

The simple fact is that roasting is exactly like espresso, the problem is almost always the person, not the machine.

[hbuchtel]

another far stretch, buy lavazza. ok, not ideal, but still a great tasting bean, and not anywhere as flat as a homeroasted bean would taste, especially after 2-3 months!

I had the same experience when I switched from pre-ground "major roasting company" beans to home-roasted (brewed with a moka pot).

My hypothesis at the time was that some companies blend with the expectation that the coffee will be stale when brewed.

From the other posts here it seems the roasting also plays a large part...

Henry

[Branden]

One factor is that pro roasts come in valve bags, while home roasts are mostly stored in mason jars. This, along with less than perfect profiling will make the difference.

I have often wondered what the effects of a sealed mason jar are and how this changes the way a bean stales. When I open a mason jar, for the first few days the smell is rather flat while in comparison when I store my homeroasted beans in valve bags the aroma appears to develop to a much fuller extent.

What are the effects of CO2 that is trapped within a mason jar until opened?

Branden

[Kaffee Bitte]

And on similar lines. Are jars with one way valves a good way to go?

[DaveC]

I've always thought so, and you can make reusable ones.

http://coffeetime.wikidot.com/one-way-v ... -home-made

[Kaffee Bitte]

I've always thought so, and you can make reusable ones.

Are the one way valve jars that are sold by, say Bodum or other companies also good?

[DaveC]

I don't know, have not seen or used them. Do you have a web URL?

[luca]

This might well merit a separate topic, but one thing that I have mentioned before as intriguing me is that commercial drum roasters invariable start with a much higher drop temperature than most home roasters. Could that have something to do with it?

[LeoZ (original poster)]

i still dont understand the benefit of a start temp and calculating the drop temp. so it goes from 200 to 150, then ramps up? is this really doing much besides taking a minute off the total roast time?