I'm near the end of a bag of very good coffee from a roaster that is well-respected around here. Over the last pound or so of the bag, I've noticed a few beans that look like this:

There haven't been very many of them, and it's certainly possible that there were some in earlier batches that I just didn't see. I've recently changed the vessel I use to weigh the beans prior to dosing to one that makes it easier to look at the beans on the scale. (Not for that specific reason. That was happenstance.)

These beans were purchased at the beginning of April and split into 8 oz bags, stored in my freezer. The shots taste very good. It seems unlikely that I've noticed and discarded every bean that looks like this, and there haven't been any unexpected sink shots with this coffee, so I'm guessing that if they taste bad it must not be severe.

Does anyone know what causes this? Is it a real defect or just a visual anomaly that won't harm the taste? Is this something that most likely came from the roaster, or could my freezing have introduced it? Is it a common defect that has a name? I couldn't match it to any of these.

These are shell and shell cores, generally resulting from storage and processing, and not from roasting. The bean basically is separated into outer shell and inner core pieces, due to force.

henry's right. In the SCAA classification, shells are considered a 2nd class defect; that is, one that doesn't taint the cup, but does detract from cup quality. Five shells per 350 grams is equal to one full defect. Five full defects or more disqualifies a lot from specialty status.

So a few shells shouldn't be a problem; but if there's a handful of them, I'd consider it a warning sign about the overall quality of that coffee.

Thanks to both of you. That's a defect I hadn't seen anything written about before.

another_jim wrote:So a few shells shouldn't be a problem; but if there's a handful of them, I'd consider it a warning sign about the overall quality of that coffee.

I'll keep an eye out. I haven't noticed many, but I hadn't really been watching for them. I got those 3 dosing an 18g shot this morning and realized I had seen a few previously, so I decided to ask. I think this coffee is up for the favorite blends of 2011 testing, so I'll be curious to see if any of the testers notice them and consider them significant enough to report.