Since the "Favorite Espresso Blends 2011" thread is locked for the reviewers' use, I'd like to post a question. A lot of real and digital ink has been spilled over the differences (real or supposed) between air and drum roasting. Gimme's John Gant is a famous advocate of air roasting. Could any of the reviewers detect any specific air roasting impact on this blend?

Gimme has been using drum and air and convection roasters. Here's some pics that show them, the Andy assisted PID controls, and most importantly, Colleen Anunu, their current roastmaster.

I do not know on which roasters Leftis was done. But here's an odd fact ...

... after roasting on a small drum for a year, I recently compared the roasts I get on it to the ones I used to get on my PIDed airroaster. They were indistinguishable. My take on this is of you have two controllable roasters, it's the taste of the person doing the roasting that counts.

Thanks for the link, Jim:

we have two fluid bed air roasters that are modified in different ways to have more control over how the coffee is heated, and a small drum roaster that we roast our boutique lots on

So, I think we can safely assume Leftist is air roasted. I was fascinated, by the way, to see that 200 people turned out for their roastery tour. I like to joke that, when I lived in Ithaca, the best coffee was No-Doz.

another_jim wrote:... after roasting on a small drum for a year, I recently compared the roasts I get on it to the ones I used to get on my PIDed airroaster. They were indistinguishable. My take on this is of you have two controllable roasters, it's the taste of the person doing the roasting that counts.

Hmm... I'd agree that you could hit the same target on both an air and drum roaster, and another_jim's testing proves that in spades. This doesn't necessarily prove that you can't introduce flavor differences, or does it? I can taste the difference between air-popped popcorn and drum-popped popcorn. Wouldn't coffee be subject to similar influences, or is the point moot because the beans aren't directly consumed?

If you did not tell me it was fluid bed roasted, I would not have know it. Then again, you would need to have the same blend roasted in both types of roasters to see if there was any distinguishable difference. I only have one data point to compare, not much good without the second data point.

It's just a tool.
What matters is how you use it.

An unmodified Sivetz is one on which you have no genuine granular temperature or airflow control apart from using a gate valve to reduce the amount of gas coming into the burner. At best this allows you to extend an 8 minute roast to about 11 minutes. I refer specifically to the 1/4 bag machine as I have no experience with other sizes of Sivetz roasters although I have worked on both 1995 and 2006 vintage machines (former has burner in an attached chamber and latter uses an external Midco burner that fires into a funnel from a short distance away.) If doing multiple back-to-back roasts the 11 minute time can drop to about 9:30 when the unit gets really hot.

Subsequent to working on the Sivetz (which belonged to a cafe for whom I worked part time) I owned and roasted on a Diedrich IR-12. In my limited experience the Sivetz roasted coffees tended to have a brighter profile that seemed a bit more acidic. This characteristic was actually a benefit with the Indonesian coffees I roasted, was a neutral factor with the Centrals (I only had a chance to roast Guat and El Salvador) and IMHO it was a slight shortcoming when roasting some African coffees (Yirgacheffe and Tanzanian Peaberry in particular - the Kenyan AA did much better on the Sivetz.)

The shortcoming was the lack of any capability for slowing down the ramp up to specific target temperatures at various points in the roast. My results were very consistent but not always optimal based on my taste in coffee. I slowed down roasts with the gate valve and also allowed the unit to cool down a bit after every X number of batches in order to be able to keep my roasts at 10 to 11 minutes. The person who took over my roasting responsibilities for that cafe does not use the gate valve to extend roasts as I did and more than a few of my former customers have commented that they enjoyed the coffee I roasted more than what they are drinking there now.

With the Diedrich the option to control temperature rise and profile is much better but that machine is very particular when it comes to cleanliness of the airflow path. Any deviations from a strict and regualr cleaning schedule for all parts and pieces in the air pathway can result in a smokiness or "roast flavor" in the profile (I know as I have experienced this and others who tasted some of my Diedrich roasted coffee detected this on certain batches.) This is not a shortcoming of drum roasters - it's simply a characteristic of that machine and can be overcome by good maintenance procedures. I've had stellar coffee roasted on an IR-12 - some of my own and also from both Victrola and Ecco. I've also had some great coffee roasted on fluid bed machines.

Is there room for both drum roasters and fluid bed roasters in the same roastery (or hybrids such as the Loring Smartroaster that are somewhere in between?) In my opinion yes.

I think fluid bed roasters (although I would not want to work on one again unless it had modified controls) have the benefit of delivering very consistent roasts with a short learning curve for the operator, minimal need for constant monitoring throughout each roast and minimal maintenance requirements. Risk of roasty or smoky flavors in the taste profile is nearly non-existent (assuming you do not grossly over-roast.)

Drum roasters have the benefit of allowing more granular control of roast profiles if in the hands of the right operator. I don't consider one type to be "better than the other and in many cases can deliver exactly the same result - but I think there is room for and benefits form both.

It's just a tool.
What matters is how you use it.

Absolutely right. That being said... what tool you select can make a difference.

malachi wrote:It's just a tool.
What matters is how you use it.

+1

Like the other poster in the thread it really matters on the person using it. One my favorite shops has now let a employee roast the coffee as opposed to the owner and the quality has dropped off and become inconsistent, thus they lost a customer and got an update to their yelp review.

Point well taken but it's one of the owners who is now doing the roasting. When I trained him I explained the rationale behind longer roast time on the fluid bed and showed him how I was achieving it. He appears to be more time driven than I was and... trying this delicately... will not be as amenable to such a dialogue as I might hope. Don't get me wrong - I think their coffee is still more often than not the best tasting cup of brewed coffee in town but it could be better.