Baked Not Baked, All Wrong and Well Done -- Roast Advice
On the public Coffee Roaster Forum of Facebook, Cliff Lawson courageously posted a roast profile of coffee that tastes great, asking for any input about his approach of the roast.
This set off an avalanche of responses by people who of course had not tasted the coffee or even seen the beans.
Some comments were helpful, pointing to better understanding of the profile legend and what the colored lines technically represent, others were very critical and a few highly experienced fellow roasters had very wise advice. All worth remembering and everyone had the best of intentions, not meaning any harm.
Of course any profile is only one representation of what has happened. Terroir, roast color, moisture loss, and very importantly roasting machine architecture, probe choice and placement, measuring device, data accuracy and communication speed also play a huge part in what might determine or explain a successful roast.
Last week, a friend succeeded in copying on his own little roaster a roast profile which had been very successful for the same beans on a very different machine but the result was awful. We tasted it together and I tried to come up with tips for his approach but I had absolutely no clue so I just admitted that.
Finding out what approach works best on a different machine can be a lengthy blindfolded search as one slowly gets to be familiar with the machine characteristics. It's not easy (nor necessary) to speed up the learning process.
A succession of roast profiles for a given bean, measurements of the other data before and after the roast and the feedback about tasting can help me to ever closely reproduce the better roast of the set. For me, the roast profile is one of the very helpful tools in the entire process.
In preparation of a roast of a newly arrived order of greens, I usually observe the beans, measure the moisture using the Wile device and then select an Artisan profile of a recent roast of beans with similar characteristics. This often helps to get a foothold and roughly know what to expect -- a slow warm up in the beginning for instance or an especially explosive outbreak of heat just before FC can be heard, or maybe a tendency to lose too much energy when a gush of airflow is applied disturbing the driving force of the development. I have an idea about the temperature at which FC may occur, the possibly best temp to Drop the beans and the "Area Under Curve" the bean may need. During roasting all of this needs to be adjusted of course but these are usually more fine tuning adjustments than radical corrections to avoid disasters. After the roast I do more measurements (weight, moisture of roasted beans, color by Tonino) and add these data to the profile which will be an Artisan background for the next batch of the same beans.
Sharing these results online sometimes yields weird 'advice' and the friendly thread saved below illustrates this wonderfully.
The "Rate of Rise" puzzles a number of roasters who assume that if the line seems flat, the temperature remains the same even though it can be seen that the measured Bean Temperature is steadily going up and therefore the pressure inside the bean cells continues to increase, facilitating the many high pressure reactions that create our coffee delights.
Other terms sometimes confusing even those who use them are 'convection' and 'conduction' and luckily roasting machines have no digital displays indicating what percantage either of these is 'on' at the time. The same goes for 'infrared'. If I used the terms I'm sure I'd get tangled up in them as well so I avoid it but some well meaning fellow roasters are less cautiously 'winging it' which may cause misunderstanding.
This set off an avalanche of responses by people who of course had not tasted the coffee or even seen the beans.
Some comments were helpful, pointing to better understanding of the profile legend and what the colored lines technically represent, others were very critical and a few highly experienced fellow roasters had very wise advice. All worth remembering and everyone had the best of intentions, not meaning any harm.
Of course any profile is only one representation of what has happened. Terroir, roast color, moisture loss, and very importantly roasting machine architecture, probe choice and placement, measuring device, data accuracy and communication speed also play a huge part in what might determine or explain a successful roast.
Last week, a friend succeeded in copying on his own little roaster a roast profile which had been very successful for the same beans on a very different machine but the result was awful. We tasted it together and I tried to come up with tips for his approach but I had absolutely no clue so I just admitted that.
Finding out what approach works best on a different machine can be a lengthy blindfolded search as one slowly gets to be familiar with the machine characteristics. It's not easy (nor necessary) to speed up the learning process.
A succession of roast profiles for a given bean, measurements of the other data before and after the roast and the feedback about tasting can help me to ever closely reproduce the better roast of the set. For me, the roast profile is one of the very helpful tools in the entire process.
In preparation of a roast of a newly arrived order of greens, I usually observe the beans, measure the moisture using the Wile device and then select an Artisan profile of a recent roast of beans with similar characteristics. This often helps to get a foothold and roughly know what to expect -- a slow warm up in the beginning for instance or an especially explosive outbreak of heat just before FC can be heard, or maybe a tendency to lose too much energy when a gush of airflow is applied disturbing the driving force of the development. I have an idea about the temperature at which FC may occur, the possibly best temp to Drop the beans and the "Area Under Curve" the bean may need. During roasting all of this needs to be adjusted of course but these are usually more fine tuning adjustments than radical corrections to avoid disasters. After the roast I do more measurements (weight, moisture of roasted beans, color by Tonino) and add these data to the profile which will be an Artisan background for the next batch of the same beans.
Sharing these results online sometimes yields weird 'advice' and the friendly thread saved below illustrates this wonderfully.
The "Rate of Rise" puzzles a number of roasters who assume that if the line seems flat, the temperature remains the same even though it can be seen that the measured Bean Temperature is steadily going up and therefore the pressure inside the bean cells continues to increase, facilitating the many high pressure reactions that create our coffee delights.
Other terms sometimes confusing even those who use them are 'convection' and 'conduction' and luckily roasting machines have no digital displays indicating what percantage either of these is 'on' at the time. The same goes for 'infrared'. If I used the terms I'm sure I'd get tangled up in them as well so I avoid it but some well meaning fellow roasters are less cautiously 'winging it' which may cause misunderstanding.
Enjoy the (at times fun and even hilarious) thread! As Cliff concludes,
"This thread should be a teaching tool for decades" ;-)
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