Hi,
Is there an option in Aillio that detects the 1st crack automatically? Or, in general, how can I detect the 1st crack in Aillio?
Thanks,
Mohd Rafeea
You should be able to hear first crack but if you are having difficulty with that, some folks here have inserted a small microphone through the trier opening connected to a small PA speaker to amplify and help make first and second crack much more detectable.
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Typically for me FC occurs between 395 and 405 F (201 - 207 C) so I will start listening for it. Some beans will crack loud enough while some donât. Search the forums for hacks on what @gabyritaseek.qiAO mentioned.
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Hello @blacklabs
Thanks, what do you usually set as conditions in the recipe for D, F and P to have the FC between (201 - 207 C)?
Regards, Rafeea
It depends 
My initial settings for PH, D, F and P at the start of the roast depends on the batch size and what I do after as well. All my roast profiles are public on RW so feel free to look. That said, there are other roasting methods (different profiles) that other people use that can also result in similar targets. I do encourage searching the forum for keywords that interest you and see what you find. There is a lot of knowledge that have been shared in the forum posts over the years. Sorry my answer isnât a âdo thisâ answer because it really is more involved.
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It certainly does.
To elaborate on what Blacklabs said:
Most beans will crack at a specific temperature range depending on the bean characteristics.
The crack actually occurs when the moisture in the bean is heated to a steaming temperature, then depending on the bean density the steam will break through a wall and that is when the âCrackâ happens.
So here are some of the variables related to the crack:
Is the bean a high altitude bean?
If it is a high altitude bean it will usually be more dense, because it typically doesnât get as much rain/mist/moisture and shade to stay moist and allow the seed to grow larger.
Another variable is the varietal of the bean that you want to roast. Some Varietals produce bigger beans than others.
The amount of moisture in the beans is another variable. More moisture usually will make a louder crack in a higher density bean.
Most beans are shipped with an internal moisture content of ~12%
To simplify this a bit: If you apply a heat source to a bean and could measure the internal temperature of the bean, you might find that at a specific temperature for that bean, the internal moisture will turn to steam and then crack the wall of the bean to escape.
Most of the beans that I roast will start first crack in the range of 200C to 203C (or 392F to 397F) There will almost always be some beans that crack early and some that crack late. Those beans may have more moisture in them or have weaker walls. We call those outliers and we usually wait for a close succesion of 4 or 5 pops or cracks that happen before noting that we have truly arrived at first crack.
To summarize this so far: the Crack is most often determined by temperature.
So the second part of this is how fast you heat the beans to get to steam stage. If you apply a lot of heat the crack will happen sooner, if you apply heat slowly, the crack will happen later. But it will almost always be within a degree or two of what temperature the crack happens for that bean.
Other factors that should be paid attention to is the tyep of proceesing the bean received . the two major types of processing are Washed and Dry or Natural. There are others, but for simplifying this explanation, I am just going to talk about the two most common processes.
The washed process starts with the cherries after they have been picked and then run through a machine to remove as much of the pulp from them as possible. Then they are washed until the pulp si gone and then they are set on raised beds and dried while being mixed up often to facilitate even drying
Dry processing is where the cherries are picked and sorted for any obvious defects and then they are set on raised beds and dried while being mixed up often to facilitate even drying. One of the things that Dry or Natural processed beans have is more sugar in them because some the sugar in the pulp transfers to the bean. Sugar browns and burns at a lower temperature that the cellular structure of the main part of the bean. Natural beans have more flavors from the skin and pulp that give them the fruity flavors that people talk about.
Therefore: if we apply too much heat too fast to a Natural, we might scorch or tip (burn) the outside of the bean
It is typical to pre-heat the Bullet to a lower temperature for a smaller batch size to keep from scorching Natural beans.
Oh boy, this is getting confusing.
So: you might end up with first crack happening at 201C at 8 minutes, or you might end up with first crack happening at 201C at eleven minutes, because of a larger batch size and a lower power setting.
I hope this helps, but remember that I am just a novice at this and âYour mileage may varyâ lol
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is the 200-203 temp range youâre referring to best measured with the IBTS or the bean temp?
That is a good question.
Normally I gauge first crack based upon the IBTS. At this stage of the roast, it is more accurate. If the IBTS and the Bean Temp probe cross, THEN I start basing decisions on the Bean temp probe because the Bean Temp probe will typically be immersed in the beans and making more contact.
Thermal probes (like the Bean Temp Probe) have a lag in how long it takes them to update their measurements. Part of it is because the heat has to travel through the stainless steel sheath that the probe is embedded in, and the other is the electronics that convert voltage signals into thermal measurement numbers.
The IBTS measurements are based upon NON-CONTACT readings of surfaces. When the IBTS measures the interior of the Bullet during Pre-Heat, it is actually measuring the temperature of the surface of the drum. It canât really measure air temperature, because air is not reflective.
Something to think about is: If your Rate of Rise is very high and you are measuring the outside of the bean surface with IBTS and it is measuring reflection, what is the temperature of the interior of the bean? You might end up with the outside of the bean at a different roast level than the interior of the bean. Think of a Beef steak. The interior of the steak is medium rare but the outside edge is well done.
For my profiles, I try to flatten out the end of the profile so that the interior of the bean is roasted to the same level as the exterior.
These are just my thoughts.
There are a lot of other ideas about this.
As always: Your mileage may vary
Appreciate the time taken to respond here.
The core of my question was trying to estimate actual first crack based on temperature, sometimes hearing first crack is challenging, knowing first crack is usually between 195-200 I can listen out for it and train my ear. But I caught myself saying is it 195 on the IBTS or 195 on the bean probe.
From the response it seems most have FC at 195 on the IBTS.
Iâve found that some beans just have a quiet crack, maybe they donât have the cell structure to hold on to the buildup of pressure prior to 1st crack and instead release the pressure more discreetly. Smaller batch sizes are also more difficult to detect.
If Iâm familiar with a bean, and know itâs a âno crackerâ and Iâm repeating a roast profile, I will simply mark 1st Crack at 200C. This allows me to to have a repeatable development time based on the IBTS surface temperature of the bean which is a good representation of where the bean is in its roast cycle.
But should I settle for a no cracker? I could add more momentum to the roast to encourage a more audible and distinguishable âcollective crackâ.
Does an audible crack produce a superior cup?
If Iâm happy with the cup is it worth chasing the crack?
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195C is a good point to get intimate with the rolling cascading sound of the beans being churned in the drum, and then youâll be prepared to distinguish a change in the sound. You can make it more audible by simply pulling the trier out briefly.
My 1st crack experience seems to lie between 197C and 202C.
I think peopleâs interpretation of 1st crack may also have a lot to do with when they mark it. I mark when I hear a rolling crack, i.e. not the first few outliers.
Robusta typically cracks much later around 205C.