Logging First Crack (FC) on KL Nano

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Logging First Crack (FC) on KL Nano


Post by Yochiya » Sun 19 Sep, 2021 1:21 pm

This is quite obvious to some users, but surprisingly is not in the Instruction Booklet. It is mentioned in the Kaffelogic Roaster's Companion.

How to log First Crack (FC)
  • Start the roast by hitting the Start button (3rd button from the left)
  • Listen for FC,
  • Hit the Menu button (1st button from the right)
  • Hit the Start button (3rd button from the left)
When to log FC
  • When you hear 3 cracks in quick succession.
There seem to be many varying opinions, the most common is listening for 3 cracks in quick succession. That is, FC is not when you hear the first pop, but more when most of the beans are about to crack.

Why log FC
  • The Nano adds it to your KL Log for the roast
  • You wil see an indicator showing Development Time Ratio (DTR%) of the roast in progress.
First crack is a significant milestone in the coffee roasting process. Simply put, it signifies that the beans are near 'cooked' enough to use and no longer raw. A more complex description would be that the beans have ended the endothermic phase and have now become exothermic releasing temperature rather than
absorbing it.

The significance of this, is that from this point onward, you can decide the roast level. A light roast might be 30 - 45 seconds (or 15 - 20% of total roast time) after first crack. A medium roast could be ending the roast 1-2 minutes (or 20 - 25% of total roast time) after first crack.

This phase is commonly referred to as 'Development Time', the time that the bean is being developed, sugars are being caramelised and you are modulating to a large degree the flavour. DTR is simply the ratio of this phase in relation to the total roast time.

Whats next
  • You can use the logged FC to fine tune your roast profile or develop new ones.
  • You can find which Roast level and DTR you personally prefer
After roasting a bean a few times, you can get a good idea as to when FC might occur. This could be a specific temperature or time given a specific profile. Using this knowledge from your roast logs, you can set an estimated FC on your profile. You can also use advanced features such as boosts to combat flicks or crashes. Knowing when FC is likely to occur can enable you to develop new profiles and aim for specific DTRs.

Once you find a DTR you like, you can start making minor changes to the profile itself to experiment with the effects on the bean whilst keeping DTR locked in.

I'm not a roaster, I just want a good cup of coffee. This is intended to validate and share what I have learned. This is further intended to be simplified and 80% correct. Please feel free to correct and add to this so that others may learn from it.

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