Greetings to all,

I haven't been able to find the answer to this anywhere.

How do you measure the time of the first crack?

You hear the sound of the first bean cracking. A few seconds go by, then you hear another one, then they get faster and then there is no doubt.

Where in this process do you start timing? Same thing when it is ending.

A well known roaster was writing about roasting Ethiopia wet processed coffees. He said that you want to stretch the first crack to between 1:30 and 1:45. Thus, knowing how to accurately measure the time is important.

Many thanks in advance to those that help out.

Basically, the goal is to measure the length of time during which "typical" beans are undergoing FC. The more consistent and well-processed the green coffee you are using, the cleaner the boundaries will be on either side. With a bit of experience roasting a particular coffee in a particular roaster, you should start to get a sense of when you should be expecting it to enter and finish FC, in terms of both temperature and time. If a few stray beans pop quite a bit earlier than this, I wouldn't want to start the clock, because that would be misleading regarding what the bulk of the bean mass is doing. Similarly, a few stray pops well after the rest has finished should also be ignored.

Unfortunately, the boundary between a few stray pops and "first crack is getting started" can be blurry, especially when roasting more inconsistent coffees, so there is no crystal clear set of directions I can share on this. You just have to get used to your roaster, and develop a feel for it.

pete51 wrote:Greetings to all,

I haven't been able to find the answer to this anywhere.

How do you measure the time of the first crack?

You hear the sound of the first bean cracking. A few seconds go by, then you hear another one, then they get faster and then there is no doubt.

Where in this process do you start timing? Same thing when it is ending.

A well known roaster was writing about roasting Ethiopia wet processed coffees. He said that you want to stretch the first crack to between 1:30 and 1:45. Thus, knowing how to accurately measure the time is important.

Many thanks in advance to those that help out.

For start of first crack, I've heard it said that you wait till 2 or more beans snap fairly close to each other. Maybe within 3 seconds or so. This is my practice as well.

As far as stretching first crack, most of us seem to end the roast after that development time. So stretching first crack 2 minutes, the end of that 2 minutes is also the roast end time.

That said, if you DO hit second crack and like your beens roasted to that level you learn where your roaster hits second crack. You note the bean temperature and take notes. From there you can back up and find the spot where first crack stopped, or was the slowest. For me first crack slows pretty gradually and it's difficult to really have a definite ending point. I look for the point that is slows substantially. Maybe a pop every 10 seconds.

I don't know if your Hottop has a bean temp probe, but that really is important to figuring this out. With my probed Hottop, I hit first crack at a bean temp of 395-400. I hit second crack about 440. But I usually end the roast between 415-430f. This is between 1:30 to 2:20 past the start of first crack. After lots of observation, it seems my average first crack ends about 420f. But temps can not be translated to other equipment. We each end up with our own unique temps where the milestones happen.

So after lots of observation, and lots of roasts from the same green stock, you figure out what taste balance you like and stop the roast at that point. You don't really have to know when first crack ends, you just repeat the profile and stop the roast at the same temp.

You have to establish sensory markers which are closely tied to the realities of bean behavior. Unfortunately, they'll still be somewhat arbitrary and you might find that they don't comport with someone's recipe as closely as you might like. There's no "right," measure. The best you can do is try and establish how closely what you're doing matches the guy's whose profile you're trying to learn.

I call 1stCs (first crack start) at the 6th crack; and 1stCe following 3secs without a crack, "back dating" the time by 3sec. Those rules written on tablets of stone by a flaming finger. You're free to work out your own markers.

The key to consistency is associating these sensorial markers with real time, accurate beab temperatures during a "milestone" roast, so you can use them (checking the temps as you do) every time you roast that bean afterwards.

The bean temperature RoR (rate of rise) at which you enter exothermia just before 1stC will do more to determine the length of 1stC than any adjustments you can make during 1stC; and after exothermia -- about half way through rolling 1st -- the RoR will fall significantly if the roaster isn't pumping too much heat into the beans.

Rather than establishing a particular time goal for the entire process of 1stC, it makes more sense to me to anticipate it and reduce heat 10F - 20F before 1stCs, to control the RoR following exothermia in order to get the right amount of total time for the Development interval (the period from 1stCs to Drop).

I was a "sensory" guy until recently, but in the last couple of years did some reading and took some instruction which got me serious about using real time plotting, and my understand of the roasting process as well as my roasting itself are much the better for it. To the extent that artisanal, craft roasting means doing things on purpose and with nearly complete control, real time, BT plotting is huge. Lacking real time, accurate bean temperatures, you can still do some wonderful roasting; but it limits your precision.

Sic transit gloria mundi,
Rich

boar_d_laze wrote:To the extent that artisanal, craft roasting means doing things on purpose and with nearly complete control, real time, BT plotting is huge. Lacking real time, accurate bean temperatures, you can still do some wonderful roasting; but it limits your precision.

+1. This point cannot be overstated; the more you know about what is going on in your roaster, the easier you will find it to improve through trial and error.

another_jim wrote: 2. the moisture content of the bean and the length of time spent heating up to first crack will affect its onset and length.

Hi another_jim, can you elaborate on the length of time heating up to FC affecting its onset and length?

All good information!

I have been using the Amprobe with EricC's good probes and can get good information out of the roaster but I have yet to master the Artisan to computer/plotting. I need one on one button pushing education