Why the surface of roasted beans crack???

[Merc]

Hie,

I am currantly roasting coffee at home with my I-Roast 2. It is a really great home roaster. Every batches is even. But, when i try for a darker roast (full city), the surface of the coffee beans starts to peeled off and when the roast is done, I can see some black patches on some of the beans where the surface peeled off. Everything is fine and great when I roast it at city roast. For the information, I am using some bolivian organic coffee beans.

The question is, what made the surface peeled off? Is it because of the quality of the beans? Is there a solution for the problem i met? Thanks.

 

[topher]

are you speaking of divits? Where the bean looks like it is chipped? You could be speaking of "pitting" or "divits" that is where moisture builds up in one area and POPS through the surface of the bean....this could be due to improper storage or it wasn't dried evenly..what coffee are you roasting or is it all your coffee?

 

[ElPugDiablo]

If it taste good then it is not a problem, other than ugly beans. Other than don't roast it dark I don't think there is a solution. I get that from time to time from Sumatra, but rarely from Central Americas.

 

[BeanGrinder]

Roast Magazine had an article in an early edition that showed the many different defects in roasted beans and the reason for each. There are several variables in the roasting process that will impact the condition of the beans, including the quality of the bean, moisture content, rapiditiy of increase in temperature.

There is no doubt that the better the bean, the better the roast. If you are using really good beans, they're more likely to look good after they are roasted.

If your roaster heats the beans too fast, you'll end up with pocks or black spots on the beans.

Here is a very important tip - if you roast the beans too long they turn really black and oily, then turn to ash.

If I come across my back issues I'll try to offer a paraphrase of the article. Good magazine. I regret that I let my subscription laps.

-BG

 

[Jackson]

I roast at home too!! I beleive you are roasting too hot. If you can roast a batch in under 6 minutes, you will have pits. When I roast over a six minute roast period, I do not notice any pits.

 

[topher]

Jackson..I am not a home roaster but if you only roast to 6 mins then how do you roast french roast...or do you achieve a french roast in 6 mins? Like my buddy BG said "too hot" try coming in slower at a lower temp. Tell us how you make out.

 

[Jackson]

I wish I could control the temperature of my roast. I am one of those poor guys forced to use a popcorn popper. Trust me, I can kill a batch of coffee in 4 1/2 minutes in my popper. One good thing about winter in Ohio, when I roast outside, I can roast a full city in about 12 minutes.
I roast outside all the time now. I have about 4 months to upgrade my roaster before the spring thaw arrives. If you have any good options, please pass them my way!

 

[Merc]

Erm....... the taste of the coffee is nice. Just that I feel it a little bitter which is not really nice. The batch I am roasting right now (today) is really even. No more patches of black spots. I am using the same bean as before just different pack that bought at diffferent time. I am looking forward for the taste tomorrow.

I don't think I over roast it. Since I am using i-roast, I roast it to full city in 13 mins. I increase the time and temperature slowly and the final temperature is around 430F. But I am going to try a new setting to see whether there will be a nicer combinations.

 

[Merc]

I found out that most of my roast (almost 100%) who get into rapid second crack will tend to have their surface chipped off (divits as what topher said). I try 2 different beans although both come from the same country, it still have the same results. Is it a common scene? will it affect the coffee due to it has dark patch at the chippied place. Is there anyway to advoid it? I am using bolivia beans organic and bolivia fair trade. I am using i-roast 2. the final roasting temperature is 220 celcious and the warm up temperature is 190 celcious