Batch #9, September 2011

Preparing for the roast

Going back to my SweetMaria's sampler, I decided to try something different, and go with their Sumatra Grade 1 Mandheling (dry processed).

Tom describes it as:

This is a deep, brooding, bass-note coffee, with an undertone of mildly earthy dark chocolate. The dry fragrance has a chocolate bittersweet taste, and just a trace of foresty earth and floral herbs. The wet aroma has a bit of peppery pungency, molasses, and Ricola-like dark herbal notes. The cup has layered chocolate roast taste, moderate brightness, and thick body. This lot is very nice because it has a hint of fruit too: mango/peach. The finish has a slight dryness and bittersweet quality, reminiscent of Baker's Chocolate. There's a clove spice note that emerges as the cup cools. I am recommending darker roasts here, which highlight body and chocolate; Full City+ a few snaps into 2nd crack was my favorite. Fruited notes are best at City+, and are obscured when going darker, so a lighter roast is also an option for a different flavor profile.

So my goal will be the very beginning of 2C, for a FC+ roast.

Keeping the same profile (temperatures from Hottop display):
250°F Drop-in.
290°F Reduce power to 80% (just before the drying phase).
320°F Reduce power to 60% (beginning of drying phase).
In the middle of the drying phase (colour = bright green), fan at 50%.
At the end of the drying phase (colour = tan), power back to 100%.
Look for constant and significant smoke and especially toasting smells, indicating 1C is coming in 1:00-1:30.
Before reaching the first pop of 1C, reduce power to 50%.
As 1C begins and becomes more active, reduce power to 30% and raise fan to 100%.
After 1C and before 2C, adjust power to keep a positive slope on ET.
At the first snaps of 2C, eject.


The roast

Batch weight: 225g.



00:00 255°F Drop-in. (H100) (F0)
02:00 293°F (H80)
03:30 321°F (H60)
04:30 334°F (F50)
05:30 345°F Yellow.
06:30 352°F Tan. (H100)
07:00 357°F Light cinnamon.
07:30 361°F Cinnamon. Toasting aroma begins.
08:00 365°F Smoke starts.
08:30 370°F Light brown.
09:00 377°F Some continuous smoke. (H80)
09:45 383°F (H50)
10:00 384°F First pop of 1C.
10:30 388°F 1C starts.
11:00 392°F 1C under way. (H30) (F100)
12:00 397°F Sparse pops.
12:30 399°F 1C has ended.
13:00 399°F First snap of 2C? (H40)
13:30 399°F (H30)
14:30 399°F (H60)
16:30 401°F Some 2C snaps. Eject.

About 2:30 of drying time.
About 6:00 between the beginning of 1C and EOR.

225g pre roast weight.
186g post roast weight
17% weight loss.


How it went and lessons learned

Bean size for this rustic coffee is very irregular. Many beans are broken, missing some parts. Color is not uniform. Texture is relatively smooth, with a marbled finish. Right after roasting, the aroma is nice, with dark chocolate flavour and some earthy notes.

A FC+ roast.

A long roast... probably too long. Finish mimics batch #6, which was cooked... (flat ET profile and 6:30 past 1C).

I was pretty sure 2C was about to start (I heard some snaps shortly after end of 1C), so I kept the heater down, which ended as being a mistake. I tried correcting the situation by pushing the heater back to 60% but the delay with this electric element is too long to gain real time control.


Tasting

To come...


Batch #9. Sweet Maria's Sumatra Grade 1 Mandheling. FC+. Picture taken right after the roast.

On cupping... (from Learning to Roast -- "Optimal" Batch Size?)

another_jim wrote:People will disagree with me; but I'm old school on this -- you can't learn to roast by pulling espresso shots from your home roasts. Brew them instead. Then you'll have plenty of coffee for judging the roast (modern commercial sample roasters only do between 100 and 150 grams).

A roast is good for espresso if, when brewed and left to cool to about 95F, it tastes more sweet than bitter or sour.

The fastest way to learn is to practice lighter roasts, stopped roughly thirty seconds after the first crack ends, when the roast starts smelling of caramel, and no longer has irritating grassy or vinegary aromatics. For these to taste clear and smooth, with no cutting, astringent or ashy flavors, you need to get all the early phases of the roast right. Once you have that, doing excellent medium and darker roasts for espresso is a cakewalk.

Look at it this way. Roast a 100 gram batch. Brew 10 to 20 grams, keep notes, and see how consistent you can keep your roasts. Then make shots of the rest and see if how consistent you can get in the four to five shots you'll have left.

Good knowledge.

Batch #9 tasting...

I confirm roast time was probably too long, but not enough to ruin the roast. It does taste flatter than what I expected, without much brightness, with a nice body. Earthy notes are muted but present.

It makes a good cup, while not having the specificity I was expecting from a Sumatra (dry processed).

I've received my omega.ca order and should be installing the BT and ET probe by the end of next weekend.

This should mark a turning point in my roasts: gaining more control and confidence in what is happening and what I need to do.

I now need to look for more on recommended profiles and rate of rise (RoR).

Here is a quote from Working with Hottop BT probe:

rama wrote:[...]Trying to "hang out" in a certain temperature range sounds like a mistake to me. Instead I'd suggest you try dialing in a roast profile that ramps roughly 20F/min until first crack, then about 10F/min until desired state. Once you've learned you've mastered that, and how tweaking the controls on the Hottop affect the measurements at your bean probe, you can get fancier from there.[...]

Batch #10, October 2011

Preparing for the roast

This marks a drastic change in my tools. To sight, hearing and smell has been added environmental and bean temperature, along with a fantastic real time graphing tool: Artisan.

Yes, I've finally installed my ET and BT probes (see Installing ET and BT probes in a Hottop) !

I've set up a borrowed laptop running Artisan (in Linux Ubuntu) along the HH806AU thermometer/datalogger and its two type-K thermocouples.

This meant some adjustment, as I was aware that the Hottop display is not aligned with either a properly installed BT or ET. This was harder than I thought. For example, the variability of drop-in temperature recommendations (all BT) on HB forums is surprising: from 230°F up to 330°F. I chose to use an average at 260°F, or 125°C.

Artisan is preconfigured with:
Drying between 95°C and 150°C
Climbing to 1C between 150°C and 200°C
Finishing with 2C between 200°C and 230°C

This also forced me to figure why I was working in °F. As I didn't have any good reasons, I've switched to planet Earth universal unit: °C.

I therefore chose to use a tweaked profile (all temperatures are BT):
125°C Drop-in.
Before 150°C Reduce power to 80% (just before drying phase).
After 150°C Reduce power to 60% (beginning of drying phase).
In the middle of the drying phase (colour = bright green and/or as shown by BT in Artisan), fan at 50%.
At the end of the drying phase (colour = tan), power back to 100%.
Look for constant and significant smoke and especially toasting smells, indicating 1C is coming in 1:00-1:30.
Before reaching the first pop of 1C, reduce power to 50%.
As 1C begins and becomes more active, reduce power to 30% and raise fan to 100%.
After 1C and before 2C, adjust power to keep a positive slope on ET.
At the first snaps of 2C, eject.

I will be using the rest of my bag of Sweet Maria's Sumatra Grade 1 Mandheling (dry processed).

Goal: the very beginning of 2C, for a FC+ roast. 8:30-9:00 from drop-in to 1C; 4:00-4:30 from 1C to EOR.


The roast

Batch weight: 225g.



I noticed after the roast that Artisan doesn't (yet?) allow events to be reordered (or automatically reordered chronologically), hence the strange back and forth movement on the blue (heater) line.

00:00 125°C Drop-in. (H100) (F0)
02:50 95°C (H80)
03:10 101°C (H60)
04:10 116°C Middle of drying. (F50)
06:05 137°C Going yellow.
08:00 157°C Tan. (H100)
09:30 173°C Beginning of roasted aromas.
11:00 190°C Constant smoke. (H50)
11:08 192°C 1C starts.
11:30 196°C (H30) (F100)
13:00 203°C (pushing momentarily to H100)
14:10 207°C (H50)
16:00 223°C Few snaps into 2C. Eject.

About 5:00 of drying time (according to Artisan green drying phase)
About 5:00 between the beginning of 1C and EOR.

225g pre roast weight.
188g post roast weight
16% weight loss.


How it went and lessons learned

Roasting with BT/ET thermocouples, and especially with Artisan, is a real pleasure. Seeing bean temperature progress in real time on the screen feels like learning about what was happening in the blackbox directly, instead of relying only on symptoms (color, smoke, sound).

I will need to adapt to this new tool to know what to look for and when, to act appropriately on the roaster controls.

I need to shorten the first phase, to reach 1C in 8:30-9:00 instead of 11:00 for this batch.

Color seems a bit darker than batch #9, while the rest seems identical to my untrained eyes. Bean color is not uniform. Texture is relatively smooth, with a marbled finish. Right after roasting, the aroma is nice, with dark chocolate flavour and some earthy notes.

A FC+ roast.


Tasting

To come...


Batch #10. Sweet Maria's Sumatra Grade 1 Mandheling. FC+. Picture taken right after the roast.

Louis wrote:I noticed after the roast that Artisan doesn't (yet?) allow events to be reordered (or automatically reordered chronologically), hence the strange back and forth movement on the blue (heater) line.

Hi. It can be done manually. If you go to Roast Properties, Events tab, then you can edit the events properties (time, etc).

Cheers

Summarizing roast profiling knowledge: an attempt

I've been reviewing references to see what I need to learn/remember while roasting, now that I can see BT. Any feedback from experienced home roasters will be gladly appreciated.

These are general guidelines, adjustments to these are what roast profiling is about.



Time:
General consensus seems to be:
- From drop-in to end of drying: 5:00 to 5:30
- From drop-in to 1C: 8:30 to 9:30
- 1C to EOR: 4:00 to 4:30

This seems valid for my machine (Hottop) but might not for another roaster using a different process (a different mix of conduction, convection, radiation heat transfer). Total time might change from roaster to roaster; what is important is the proportion of time spent in each phase.

These timing guidelines correspond to a general proportion of 4:3:3 (Drying : ramp to 1C : 1C to EOR).

another_jim wrote:My feeling is that it is the proportion of time spent in each phase of the roast that is more important that the overall time. If I use a 3/3/3 profile (warmup, ramp to first, and roast finish) on my air roaster, and a 4/4/4 on my drum, the results are usually very much the same.

Temperature:
As stated, the recommended drop-in temp seems to vary a lot between forum contributors (from 110°C to 200+°C). For the Hottop, I've seen anything between 120 and 175°C. I've used 125°C in my latest roast, but I don't have a good idea now if this is adequate / optimal. I will probably try something higher next time.

For the other phase transitions, Artisan pre configured parameters are:
- Start of drying phase: 95°C
- End of drying phase: 150°C
- 1C: 200°C.

From my own roast (batch #10) :
- End of drying phase: 152°C
- 1C: 192°C.
- 2C: 220°C


Rate of rise (RoR):
Rama recommends a roast profile that ramps roughly 20°F/min (11°C/min) until first crack, then about 10F/min (6°C/min).

Never should the RoR become negative (BT decreasing).


BT and bean chemistry:
From Is flavor dependent on rate of change?, flavors form at different temperatures:
>150°C malty-bready-savory Maillard flavors
>200°C caramels
>218°C distillates


Other recommendations:

From Is flavor dependent on rate of change? :

another_jim wrote:I'm always on full brake going into the first crack, since I'm switching from the fast ramp to the first to the slower finishing ramp. I've had nasty, grassy results going through the first crack fast and then braking; so now I always brake before it starts.

From Ways to eliminate the acrid acidity:

another_jim wrote:[...]excessive grassiness and acidity are the bane of light roasts. The conventional wisdom on this is
-- that you need to be up around 390F before you can roast out the acids. Above this temperature, the acids break down.
-- Prior to that, between 300F and 390F, the acids remain and the sugars and amino acids are turned into nutty, woody and malty tasting Maillard reaction compounds. A fast ramp through this zone to the first crack preserves some sugars from this reaction and can balance the acidity.
-- lowering the amount of water in the bean by drying the coffee longer, from 200F to 300F, will speed the breakdown of acids, and produce lighter roasts without grassiness. However, drying too long changes the roast chemistry for the worse, aromatic compounds do not form, the roast will taste flat and slightly charred.

I'm not exactly sure what you did; but perhaps slowing down below 300F and speeding up from 300F to 390F can help.

First of all, thank you for sharing all of this! I have a couple of questions;

1. On your HotTop, how are you gauging 80% heat?

2. Can you post more pictures of your thermocouple installation, including the exterior of your roaster? I'm looking to do a similar installation.

Thanks again. It's been a great thread!

Hi Rick,

1. I have the Hottop KN-8828B-2 model. Power can be adjusted in 10% increments (0-100) and fan in 25% increment (0-100). 80% heat is power set to 8 out of 10. It can be adjusted on the fly and saved after the roast to be "replayed" in a next roast (it can remember three programs, plus its own built-in). I don't know how accurate this setting is from roaster to roaster. The latest models are supposed to be voltage independent but I'm pretty sure a "8" on one might correspond to a "7" or a "9" on another one.

2. As there is already an excellent thread on this, I've added the pictures you asked for in it : Installing ET and BT probes in a Hottop. Add to this a laptop running Artisan, wired to the HH806AU* with a USB cable, a good range hood (venting to the outside!), some good beans and an overstressed operator and you get the whole picture.

Thanks for the feedback, I hope it is useful to others, it certainly is for me.

* If you need to buy a digital thermometer/data logger, refer to Choosing thermometry equipment for home roasting.

Had a long response formatted and wasn't logged in and lost it all.

Thanks for the info and pictures! I'm probably going to marry your installation with this one. I like the receptacle he used on the back of the HotTop.

I run the KN-8828P-2. I'm not sure if one click of the plus or minus button on it equates to a 10% heat adjustment. Does anyone here know the answer to that one?