Hi all,

I've been roasting for 2 years now on the Huky 500 - a had roaster with 500g capacity and I'm quite pleased with my results. However, I have always wondered how other roasters make an adjustment to their roasting profile for a certain bean based on the taste of their previous roasts.

I read all the Roast & Learn together threads - where people write that based on their previous roast they decided to change their roasting profile in order to achieve other taste, and I wonder - why & how you decided on that specific adjustments? For example - how do you know what will be the result of extending the drying phase?
Or making the ramp phase shorter?

It will be great help for me if you can elaborate more about it.

Regards,
Ziv Sade

This is a great question.

One of the useful espresso heuristics I learned here was Jim Schulman's "For sweeter espresso, dose lighter & grind finer". It's a heuristic that specifies a continuum and how to make practical use of that continuum.

Those kinds of rules of thumb are quite helpful for managing a complex process-- lightening the cognitive load while we learn until we're ready for further detail.

I think there are a couple of ways to look at this. I'm taking a bit of a cognitive science approach.

Note that research indicates that in general, novices tend to focus on the micro view and making small concrete changes to force their process to get the result they want. In contrast, experts tend to model the entire situation and work their way forward at a conceptual level. So what I'm suggesting here is considering an expert approach of the roasting process as modelled within different roasting paradigms.

What would those roasting paradigms look like?

GOAL EXPERIENCE --> MANIPULATING PARAMETERS BASED ON --> ROASTING PARADIGM TO EMPHASIZE ASPECTS OF --> ROASTING SCIENCE

1. Forward-looking macro view -- what is your overall goal for the coffee experience (aroma, flavour, texture, balance) and what roasting paradigms can address that?

-- types of goals (could use some descriptions of groups of characteristics belonging to types of experiences)
--- I've had tea-like brews with delicate florals and sweets
--- I've had rich, balanced (sweet and acidity) oily brews and espresso-derived drinks

-- roasting paradigms to address roasting goals (could use some names and definitions of the reasoning behind the paradigms)
--- broad combinations of time, temperature, air, ratios
Examples
--- Nordic light roasts
--- Scott Rao high starting temps and reducing rate of rise over time to max sweetness
--- variations on start/finish time (fast start slow finish, slow start fast finish)

-- roasting science (what happens during roasting -- the science used by the paradigms)
--- bean types
--- processing types (wet/dry)
--- effects of temperature
--- effects of time

2. Forward-looking micro view -- given a chosen goal and roasting paradigm, what adjustments can be made to increase / decrease certain characteristics?

-- to reach a goal, within a paradigm, while pulling out more or less experiences within that goal:
--- types of adjustments (temps at different phases, temp adjustments, fan adjustments, speed adjustments, phase ratio adjustments)

3. Backward-looking trouble-shooting view -- given certain troublesome characteristics, what can be done to address them?

-- novice troubleshooting
--- focusing on the result and tweaking parameters blindly without a model

-- expert troubleshooting
--- modelling the roast as performed and considering how to adjust the entire model
--- this means understanding the desired roast experience, the current roasting paradigm being used, and how that paradigm leverages the science
----- an expert level analysis might determine that a change of paradigm is required, or that given a paradigm, a whole set of characteristics must be adjusted in concert based on their relationships

Maybe this is already available somewhere... but synthesizing and organizing info as I'm learning helps me in any case. Plus I'm vegging a bit after finishing a major task.

One of the great ways of finding this out is to do multiple roasts of the same bean trying to isolate the one variable you want to change (such as the length of the drying phase) and compare the resultant coffees to see what differences the profile makes. This may be the best way to approach things as it's done on your roaster under your conditions. You can also read articles that discuss these subjects, there's several roasting articles on the CoffeeShrub site where they do these experiments and discuss the results here.

More info in Sweet Maria's library here as well.

hi all. thanks to David & Chris for their replies. i would love to hear the opinion of other in this forum.

i thought that this topic will promote endless discussion, since to me this is the most interesting issue relating to roasting coffee. i mean - what could be more interesting then to know how modifying a certain profile will affect the taste and characteristic of the coffee.

i've read almost every article that i found, and also most of the books, and i keep experimenting with profile, like everyone else, but from other members in the forum, i see that they change something in intention to get certain taste or characteristic, and i wonder how do they know that this change will give them the required result?

please share your knowledge.

Regards,
Ziv

Ziv Sade wrote:i see that they change something in intention to get certain taste or characteristic, and i wonder how do they know that this change will give them the required result?

Practice, practice, practice.

And nobody "knows", we hypothesize, experiment and keep meticulous notes on results.