HELP! What's happening to my beans?

[Jhon Dolton]

There seems to be a massive misconception between tipping, scorching, blowing, and burning.. Part of the problem is there's no naming convention – does “roaster” refer to the person or the machine; is “dropping” taking the beans out or putting them into the drum? Is “tipping” and “scorching” the same thing and how can we spot the difference?

Well, I don't know who decides on the precise naming conventions, but listed here is my undertake it:

Tipping
The word “tipping” probably identifies the phenomenon where the “tip” of the bean burns black. That makes sense in my experience, at least.

Just how to “spot” Tipping

Tipping happens when the beans experience any temperature excessive for the bean's heat-transfer coefficient. i.e., there's so much energy (heat) around a specific area of the bean that the bean cannot absorb/conduct/disperse the energy fast enough. The only real choice left would be to burn because area.

An example can be found in virtually any form of meat grilling. A simple lamb chop on the grill has tipping around the edges starting a coffee roastery. This really is brought on by too much heat at any onetime, inducing the meat to char instead of cook. This is exactly what goes on to the beans: there's too much heat for the bean to occupy, so it burns.

The causes of Tipping?

So, when does tipping occur? The fact is that people don't know exactly. This is above tells us so it could happen at any time, whenever the temperature is excessive throughout the roast. It could happen due to excessive a charging temperature (the starting temp), excessive a slam during roasting…too much heat anywhere!

Another question is whether this really is brought on by convection or conduction heat? Quite simply: is the drum too hot or is the air too hot? The clear answer is: either. Tipping is a factor of the beans, not the surroundings, the roaster, the drum, or air temperature. The truth is that the coffee bean cannot handle it.

Go through the image below:

Tipping
Photo Source: www.sciencedirect.com

The colours show the difference in temperatures inside the beans. It is clear from the image that, if anything should burn, it is the tips of the beans! But this changes with regards to the bean: try finding tipping on peaberries. Since the peaberries are round and has almost no distinct “tip”, the odds of tipping happening are much smaller in peaberries.

What's the effect of Tipping you roast?

So, is tipping a negative thing? That's a concern only the drinker can answer. Allow me, as I cannot stress this enough:

TASTE YOUR COFFEE!

Quite simply, if the coffee tastes bad, then tipping is bad. If your coffee tastes good but you have tipping, then surely tipping is not just a bad thing! Could be the “tipping” on the lamb chops a negative thing? No, we all love only a little char-grilling on our chops. But surely this really is per definition a burned chop? Well, possibly so, but it still tastes great!  The odds of tipping affecting your roast to the stage of experiencing to dump everything is very slim.  Chances are that the chosen profile or roast degree is way off, and that tipping is a really small area of the problem.

Scorching
So, if tipping is a burnt spot on the tip of a bean, then what is scorching? In my experience, scorching is bad practice. Definitely not a negative tasting bad practice, but one that points to inexperience on the side of the roast master.

Scorching happens when the bean touches a floor that is too hot for the thermal conductivity of the bean. Just like for tipping, but almost exclusively brought on by conduction heat. In layman's terms: your drum was too hot! Here is another cooler charge temperature or decrease the ramp-time of one's profile to negate any scorching. You shouldn't have to scorch the beans to attain your selected roasting profile.

Scorching is different from tipping in so it typically presents on the flat side of the bean. It is a larger spot that is burnt black.

Some tips about what scorching looks like:

Scorching
Photo Source: www.perfectdailygrind.com

Cratering
There is of confusion between craters and tipping. The 2 are VERY far apart. Cratering happens near or into second crack where the pressure inside the beans is released at this kind of higher level that the bean's surface cannot handle the release. This really is per definition “second crack”, but in case of cratering, the 2nd crack was brought on so much so it affects the structural integrity of the bean and literally blows an item off when the bean releases the built-up gasses inside the bean.

Crating
Photo Source: www.fullcoffeeroast.com

What's the perfect solution is?
If you decide that tipping, scorching, or cratering is the cause of any unwanted flavours in your bean, here's how to proceed:

Tipping: Lower your charge temp and execute a slower, gentler roast.  Increasing your convection heat also needs to help, along with increasing the batch size and drum speed.  The most effective is always to roast longer and gentler to allow your beans enough time for you to absorb and distribute the energy that you are trying to force into them.

Scorching: Lower your charge temp and boost your drum speed.  The less time the bean spends on the side of the drum, the less scorching you'll have. Try to increase your convection heat and minimize your conduction heat, i.e., transfer your time by way of hot air instead of a warm drum.

Cratering: Increase enough time from first to second crack and take a gentler approach will prevent cratering.  Dial back on your own gas pressure after you reach first crack and allow the beans carry themselves into second crack.   In the event that you force more and more energy into the batch, it stands to reason that “something's gotta give&rdquo ;.In cases like this, the whole bean is splintering apart because of one's significance of burnt coffee!

The Genio Academy, together with Shaun Aupiais from We Roast Coffee produced a brand-new online Coffee Roasting 101 course on our Genio Hub, available to all Genio customers, where he discusses common roasting defects in depth. Click on the link to see this unique module.