Q: what do I do with these?

[Damian]

The roast size depends on several things.
- The available power
- The profile
- Bean density/size

I have roasted up to 140g ok, with the only problem being, the roasted beans expanded to overfill the chamber, so some beans spilt out when I removed the chimney.

More beans and heavier beans require more fan speed to get them tumbling. Particularly at the start of the roast.
Higher fan speed may need more heating power for the same temperature.
Some people may have less heating power due to voltage supply.
More bean mass requires more heat power for the same heating rate.
More beans can have a greater exo and endothermic impact to deal with.

100g batches are a pretty safe bet, being unlikely to max out power for anyone. But I reckon, 100g has been adopted more so because people like to work with round numbers.

I roast in batch sizes that suit my use. I typically use 18g roasted bean weight for espresso. So I roast in multiples of 21.5 to 22g green weight. Typically a 110g roast to give me 5 espressos.
4 shots would be a 88g roast, which I have done when short at the end of a bag. And 6 shots is 132g which can spill over when done. So 110g works for me.

More recently I have been roasting in 3 x 103 batches, which gives me 14 espressos, which works well for our usage. But I use 110g if I am doing a single batch for whatever reason.

[kaffelogic]

Manufacturer specified batch size is 100g roasted (120g green). This should be treated as a maximum.

Manufacturer recommended batch size is between 100g and 120g green.

Users have reported varying success with 60g to 140g. If you plan to regularly use batch sizes outside the recommended 100-120g you might benefit from customising the profile you use to increase or decrease fan speed.

[fnq]

Darryl here as a new KL owner and first time poster.

Angela, in the interests of good communication and hopefully some systemic efficiency, what did you do with those beans? (presuming you didn't trade the for a cow) How did the roasts turn out, or what would you do differently next time?

Sorry late to this discussion but still curious. I have downloaded both the RTG and GTTT profiles for the different heights and plan on using when my next batch of green beans arrive.

[Angela]

Angela, in the interests of good communication and hopefully some systemic efficiency, what did you do with those beans? (presuming you didn't trade the for a cow) How did the roasts turn out, or what would you do differently next time?

Darryl, hi and welcome.

In all honesty, although Wayne's response was very helpful and I downloaded the suggested profiles, I have yet to attempt a roast with them. My focus has been elsewhere.

Earlier I was asking for a way of roasting other than by experimentation Wayne, despite being very helpful, wasn't able to offer that and had to use a " you could try " preface. In other word continue to experiment.

In a dark moment I bought a pack of supermarket beans; mistake!!

I'll keep you posted when I get a round tuit. (If I can find any locally )

PS I note your report of a satisfactory blend with RTD profiles; that bodes well.

[fnq]

thanks Angela

[Geronimo]

I'll keep you posted when I get a round tuit. (If I can find any locally )

Hi Angela

Help is on its way. Just asked my 97 year old Grandmother her secret in life, of always being able to get a round tuit. She pointed to her bookcase and her secret became obvious.

I’ve taken a photo, and hopefully, this will help you in your endeavours of getting a round tuit.

62C5CD95-A5BC-44EE-A024-0EA36E7C82C6.jpeg (962.78 KiB) Viewed 5620 times

[Angela]

Hi Angela

Help is on its way. ..
...I’ve taken a photo, and hopefully, this will help you in your endeavours of getting a round tuit.

Geronimo, your efforts are much appreciated. Thank you! And, initially, I thought the photographic image was indeed working; my inner voice started listing all the coffee I had bought and needed to roast right then.

I was excited, elated even.

But a short while later a neighbour called bringing a pathy to share over coffee and all the benefit from your Grandmother's round tuit photo dissipated. I fear the image is not enough; I probably need the hard stuff.

[Wayne]

Good day all

Thank you for the question regarding 100g vs 120g roasting samples .

I guess the easiest way to justify using 100g is because when receiving green from a green bean supplier , samples are generally sent out in 200g sample packs . Buying green coffee from a roaster , coffee is generally bought in 500g and 1kg for home roasting .
Roasting 100g gets you 2 samples from green broker and between 5-10 from a roaster selling you green.

On trial however , I generally don't find that there is a difference in roasting between the 100g vs 120g . This is after doing multiple roasts on both volumes on multiple profiles.

I do find that due to the varying density between higher vs lower altitude green, slight adjustments of the profile is sometimes needed .

Hope this helps .

[Angela]

.... I do find that due to the varying density between higher vs lower altitude green, slight adjustments of the profile is sometimes needed .....

It would be helpful to say what is adjusted in the profile and in which direction and over what range.

Also, if you are attempting to classify beans by their growing altitude - you acknowledge this as an analogue for bean density - it would be helpful if you could say what the expected density range is? In other words if you say 1200-1500m altitude, how many grams per cm cubed does that range over? I'm sure there is published work of others - are you able to point to a reference fairly readily?

Measuring dry tap-density would be easy for most of us I'm sure and would help confirm any package label. (Although I have seen reported coffee density measured strictly by displacement volume rather than pack volume and that is a potential confusion - dry pack is much easier to mesasure.)

[Beanz]

Geez, Angela, I've just got used to the notion that the Sumatran Mendhaling bean is seriously larger than the Mexican Chiapas and now you're querying bean density. Ostensibly, then, roasting levels might be similar between a larger and less dense bean and a smaller but denser bean?
Interesting question, all the same. Thanks