My Spin on Coffee Roasting Profiles

Do we really have to cup and develop a profile for every 10 pound batch of beans we buy to get a good roast?

Most of us amateur roasters buy beans at different times and different varietals from different farms. Some of the inconsistencies we face buying beans, even from the same farm, is that farm region has different environmental seasonal changes each year, different aged plants, usually a mix of varietals, varying processing environments, crops at different altitudes and harvested over different times during their harvest season. All these varying from one batch and shipment to the next.

Then our roasters have consistency issues like thermocouples and placement, bean temp, environment temp, air flow, drum speed, roasting temperature, size of roast and roast times. All this besides the different types of roasters and roasting techniques. I assume that these all vary somewhat in the way and timing you roast from batch to batch.

I've come to the conclusion that no batch of beans is the same, no roaster the same, no grinder grinds the same, no water the same, following the roasting profile is not exactly the same every time, no consistency in brewing, extraction consistency issues, and taste buds are not the same every day.

After considering all these inconsistencies, IMO the art and science of roasting has too many variables from one batch to the next to deal with a different profile each time.

As an amateur roaster, I started by studying several expert's award-winning roasting profiles and have found there is a common thread to most of their profiles. Dry time (200F - 300F) about 4 minutes, Maillard time to first crack about 4+ minutes, development time is more or less around 3 minutes.

So just like my washing machine, dryer and dishwasher that have many different cycle options, I always use "normal" when using them. Same for roasting coffee! I basically use the same profile for all my beans (http://www.bobbooks.net/ROR.htm).

I know that many experts might disagree, but I think most are fooling themselves that every bean needs a different profile to get excellent results or maybe even near perfect results. I do understand that you must have good beans to start with.

After roasting several years and having many people doing blind cupping for me scores of times, I have found that EVEN the same roasted batch will give a wide range of cupping results from different people.

I have even given people 2 separate bags of coffee from the same roast batch and they gave me different cupping results for each bag! All these differences could be on what type of car the person drives, barometric pressure, weather forecast, moon cycle, local baseball score, and sun spot activity. Needless to say, my experience is: "It's a crap shoot" and the only thing that really matters is, "Does the coffee taste exceptional!" Almost without exception, the comments from my batches are: "very smooth" and/or "the best coffee I've ever had".

The only basic thing I vary with the roasting profile is the development time to get different roasts from light to city++ and the drying time because I buy my beans directly from a farm in Nicaragua where they only harvest during last of December to spring, so if my beans are getting older I shorten the drying time up a little.

90% of my roasts use the same profile listed here are pulled at the beginning of the second crack. I always have excellent results from all who taste my coffee.

That's the fun of being an amateur roaster! Trying different beans, methods, and profiles for your roaster to get the best roast possible. The most important and best profile is the profile that will produce a coffee that "tastes good" to you and your friends.

Take my spin for what it's worth as I'm only a novice roaster and still have a lot to learn! I would appreciate your comments positive or negative.

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Bob Books


Roast Development Time and the Prerequisite for Any Successful Roast

by Scott Rao August 12, 2014

Scott Rao has been in the coffee business for 20 years as a cafe owner, roaster, author, and consultant. Scott has written four books, including "The Professional Barista's Handbook" and most recently "The Coffee Roaster's Companion." When he's not writing, Scott is usually training roasters or sipping Sencha tea in the corner of a cafe. You can contact Scott or view his books at www.scottrao.com.

Over the past decade as a consultant, I've had the opportunity to cup thousands of roast batches from more than two dozen machines, and to compare those batches' roast data to their cupping results. Upon focusing on only the most stellar, memorable batches, a few patterns became clear: One was that first crack* began at between 75%-80% in all the great batches. Put another way, "development time" was between 20%-25% of total roast time.

For six years I've been waiting to taste a delicious, sweet, well-developed coffee from a roast batch in which first crack began outside of that range. I have yet to find it. This ideal "development-time ratio" (DTR) has been valid for all roast degrees and roast times I've experienced. To be fair, I don't often cup roasts dropped well before the end of first crack or well after the onset of second crack, so I won't assume the ratio is valid for those roast levels.

Roasters have historically focused on "development time" (defined as the time from the onset of first crack until the end of a roast) and discussed it in isolation. For example, roasters have frequently asked me to taste a coffee and then said "development time was three minutes." To me, that piece of roast data is relatively meaningless out of the context of the total roast time.

I recommend roasters focus on the DTR rather than nominal development time. When roasters manipulate development time without considering it in the context of the total roast time, they often create baked flavors and destroy sweetness.

While achieving a 20%-25% DTR doesn't guarantee a brilliant roast, it seems to be a prerequisite for a successful roast. Think of it as a marker of balance: if a roast begins very fast and ends slowly or vice versa, the DTR will be outside of the 20%-25% range. I've had roasters protest that they roast successfully outside of that range, but none of them have ever, to my knowledge, verified full roast development both organoleptically and objectively - for example, with a refractometer. On the other hand, in my sample of thousands of batches tested for development by smell, taste, and refractometer, every successful roast's DTR was within that range.

I mark the beginning of first crack as the moment I hear more than one or two isolated cracks. If you measure the beginning of first crack differently, your results may differ.

Scott Rao


If you are a follower of Scott Reo and his theory of roasting development time, then this chart may be helpful.




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