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Roast Profiles - Fact or Fiction
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Thanks GB, I've watched a few of Anne's vids. Quite like her style and approach. Will definitely check it out.
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For what it's worth yochiya I stumbled on a presentation by Anne Cooper (Melbourne based roaster) at a roast seminar for Roast Magazine. If you look up on YouTube "Anne Cooper, being a more decisive roasters", you'll find it.Originally posted by yochiya View PostA roast profile can enable you to modulate or tweak the flavour. This can be achieved by extensions or shortening of the major roast phases.
Understanding the impact of the phases is something I'm really keen on digging into more.
Worth watching as she spends some time talking about the importance and impact phases have on the roast. She has done some collaborative work with Rob Hoo as well.
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flynnaus these were my findings too, as you can see from my roasts decreasing in time overall! Helps when I have 4-5 back to back roasts to do too!
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FNQ The green line in the profile is my old RoastMonitor template file. You can select a good roast and save it for later - but itâs a bit of a fiddle to do with every roast! As you can see I donât follow it very closely any more, but it has other information thatâs quite useful, like heatgun settings and basic technique etc. So once I nailed down a good approach, a saved one profile - and then use it as a reference for further experimentation.
I now find that using repeatable heatgun input changes are far more consistent for good results than trying to exactly match a profile with wildly swinging temp surfing - in the same way I find taste a better guide to getting good espresso than âexactlyâ 28 seconds
While my rig is not set up to use RM to control my heatgun (some have managed to do this) I simply use the temperature slider to log the settings on my gun, which are then displayed later for recall. So, for example, when the temp in red jumps to â55â itâs actually me changing my Bosch heatgun to 550.
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Excuse my ignorance but in DesignbyCoffee's coffeeSnob recent roast monitor charts what is the green line? (previous roast template? or intended profile?)
In the Kaffelogic, the machine uses PIDs, power control, fan circulation and algorithms to predict the intended path/movement and employ (or maybe deploy) heat /time variation - you heat gun peeps do it all on the fly- beyond my capacities so kudos to you.
Again excuse my lack of knowledge - Can you plot heat gun temp and time of changes as well as the beam temp change and time to see offset relationship?
In our little beasties ( only 100gms remember) you can definitely taste differences in the cup from two near to identical paths depending on the way the beans get there. ( so profiles with their momentum variables are definitely a THING).
As examples - reducing power in the development phase ( usually accompanied by aggressive PID restricting overtemp) produces muted and not as vibrant roasts and more rarely , but flatlining power, when the profile was wanting more than the 229-240volts (usually i have 235ish) available ( and it is nice that the KL tries to warn me) - in this instance you can usually see the struggle to keep near the profile path - but you can definitely taste if there has been an over-slow down in momentum - stall.
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Hi again Matt...
Sorry for the delay in responding, been feeling a bit out of sorts.
Anyway, to keep a long story short, I have identified three starting point temperature settings that gets the batch to the end of the Maillard Extension phase, for a Fast, Medium and Extended profile that works well with my Big Loaf BM. These HG temperature settings range from 420C, 380C and 350C respectively.
Upon arriving about 4.0C before the end of the Maillard Ext. phase, the temperature settings are moved to 580C, 540C and 510C respectively.
At the approach to the start of 1st-Crack at an indicated bean mass temperature of approx. 190C, the temperature setting is reduced to 430C and then incrementally downwards 30C at a time in an attempt to get a smooth transition through 1st-Crack, ultimately settling at a rate of rise of between 4-6.0C until the end of the roast, wherever that may be depending on the results I'm looking for.
Unfortunately though, of late I have been finding it very difficult during the transition phase because of very erratic temperature reporting from the HeatSnob at this critical stage of the roast profile. Makes it almost impossible for me to know what the bean mass is actually doing. Giving some thought now to applying the 'fix' identified by member "Lyrebird" to try and get over this hurdle.
Anyway mate, that's the long and the short of it. Still a bit of fiddling with temperature settings but much less that I was doing previously. Lots of fun...
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DesigningByCoffee Again, good info. Seems a few of us have been trying out a simpler profile.
Recently I've been trying a more linear profile and resulted in improvements in the cup ie sweeter and more flavoursome. Shorter roast times meant improved acidity - pleasant acidity that at times sparkled on the palate.Here's a KJM blend I did recently that, to my standard, turned out to be a ripper. At one time I had the belief that the Maillard dip improved the longevity of my roasts and I still think it does. This KJM blend roast was good up to the last shot. But I also bought an Airscape Medium Coffee Storage Vault which may have helped increase roast viability.
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flynnaus from lots of trial & error ? ⌠I found that a gentle, warming start then a ramping temperature increase gave the best results. I speed up or slow down a roast to deal with varietals but adjusting the starting temperature after the turning-point - but normally this is only 10-20° on the gun.
For example, with an 850g batch for most beans I normally use a starting gun temp of 410° from turning point, and then 50° increments at 75/100/125/150 measured by the probe. I used to go hard then until 1st crack and drop a lot at 195° or so â but now I drop to 430° on the gun at 175 then 390° at 185 which gives a pretty good roll into 1st crack, then small 30° drops every 5° from then on to keep a nice 3-4°/minute until just before 2C. Here's a profile of a recent Ardi batch if you're interestedâŚ
And here's a smaller 350g batch â same temperatures and process, but fan speed 2 on the heat gun rather than three gives and almost identical flavour profile, although the time can be a little faster.
Dimal I've actually been playing with a simpler profile â dropping the 'Maillard extension' dip. My brother uses an identical roaster I built him with a simpler profile, and had brews that had more acidity as a ristretto, which I'd been hunting. But I'd be interested in knowing what 'fewer step' way-points you're using now?
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Hiya Matt...
I've actually reverted back to fewer steps in the profile towards 1st-Crack, having arrived at set-points that achieve the optimum rater of rise, that then declines at the Maillard extension phase then increased once more from there to 1st-Crack. Has definitely improved the sweetness of all my roast batches, all the bean intrinsic flavours come through and seem to last right through to the last brew out of the bag and a very extended finish to boot. Mouthfeel has also improved and remained consistent. Lots of trial and error to arrive at this point, as you say...
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Interesting. Thanks for that. Why 50°? Is that an arbitrary temp increase or arrived at by trial and error? Do you adjust this for a larger batch?
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From hundreds of 350g-850g Corretto roasts I can safely say that profiles are a 'thing'.
I've just been making tiny tweaks in my ramps to 1C to try and gain a little more acidity while still maintaining sweetness and body. My usual 'flat' ramp' is to increase my heat gun by 50° at 75°/100°/125°/150° measured then dropping back from 175°, which is lovely but misses a little acidity as an espresso. Recently I tried 60/50/50/40 â same overall rise but much more acidic and less body. Then I tried 50/60/50/40 â a much more balanced result with better acidity. Look at a recorded profile and you could hardly tell the difference in shape â in the cup is s different story! Let your taste be your guideâŚ
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Thanks for sharing LeroyC that makes sense. I'm always intrigued by how different roasting is in a commercial environment than a home environment. It might seem very obvious to a professional roaster but as a home roaster I find these types of responses very insightful.
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I don't really use airflow adjustments because of the limitations mentioned above. When we're roasting on the 5kg Ambex we are often forced to close the vent at the start of the roast as even on full gas we can't keep up with the profile. This is common in winter and cooler weather (it's a pretty cold climate here and the roaster is in a small workshop type building with no insulation), but in summer and/or warmer weather we may not need to use it at all. The quality of the gas we get is factor in this as well as it's LNG sourced locally in here in New Zealand. The butane content is typically higher in winter, but varies throughout the year. We could look to purchase pure propane as the roaster is able to run on propane I believe, but it's a LOT more expensive and supply can be an issue as well as certification believe it or not. That was a long way of saying that it's just another lever to pull to keep us 'on profile'. Because of the variability in the way it's used and the lack of variable fan speed we're not able to have a set process for use of the vent. Does that all make sense? Hopefully we'll be moving to a 15kg roaster of some sort next year and it will definitely have variable fan speed. The main way we'll look to use that at the start if we do is to just slightly or gradually increase the fan speed as we move through the roast. It could be as simple as moving up one speed at about 150-170degC BT, but it could be more than that. The main reason to carry out at least this one change in fan speed is to reduce smoke levels in the drum and reduce the chances of the associated flavours that come with even lighter roasted coffees swimming in smoke for a period of time.
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First crack can be a useful marker, but not if you canât hear it. Thereâs a number of commercial roasters that due to their design you canât hear cracks (eg. Loring) so you canât rely on that audible milestone to guide you. To your point yochiya regarding âsignaturesâ Iâd say that this is only partly true in that a very good cupper/taster might be able to pick up hints of the type of roaster used or some of the features it has, but that is very unlikely to extend to the brand or make. Ann Cooper and Rob Hoos ran a course and a little competition a few years ago that a friend of mine attended. The competition at the end of the course was to taste the same coffee roasted on three different roasters and see if they could pick up the differences. He did the best out of anyone, but said it was as much luck as anything as it was virtually impossible to pick up any discernible difference. In my experience one of the things that can make the single biggest difference is airflow. I roast at home on a Behmor and at work on an Ambex 5kg drum roaster, neither of which have adjustable fan speed. I find this a limiting factor when trying to make smaller adjustments at just about any stage of the roast and itâs the one thing Iâd want to have in any new roaster. At work we only roast Peruvian coffee from one small part of Peru. So we only have a single profile and donât deviate from it (not intentionally anyway!) before first crack. Different results are achieved mostly through different drop temperatures but also occasionally by moving through and past first crack at a different pace.
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