HELP! What's happening to my beans?

[Jhon Dolton]

There seems to become a massive misconception between tipping, scorching, blowing, and burning.. The main problem is there's no naming convention – does “roaster” reference the person or the device; is “dropping” taking the beans out or putting them into the drum? Is “tipping” and “scorching” the same and how do we spot the difference?

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

Tipping
The term “tipping” most likely describes the phenomenon where the “tip” of the bean burns black. Which makes sense to me, at least.

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 certain part of the bean that the bean cannot absorb/conduct/disperse the power fast enough. The sole choice left is to burn for the reason that area.

An analogy is found in just about any form of meat grilling. A straightforward lamb chop on the grill has tipping across the edges. That is brought on by too much heat at any onetime coffee bean roaster machine, evoking the meat to char as opposed to cook. This really is what goes on to the beans: there's too much heat for the bean to use up, so that it burns.

What causes Tipping?

So, when does tipping occur? Truth is that people don't know exactly. The meaning above tells us that it sometimes happens at any time, whenever the temperature is excessive through the roast. It sometimes happens as a result of excessive a receiving 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 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.

Consider the image below:

Tipping
Photo Source: www.sciencedirect.com

The colours show the difference in temperatures in the beans. It's 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. As the peaberries are round and has minimal distinct “tip”, the chances of tipping happening are much smaller in peaberries.

What's the aftereffect of Tipping on you roast?

So, is tipping a bad thing? That's a question 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 really a bad thing! Could be the “tipping” on the lamb chops a bad thing? No, all of us love a little char-grilling on our chops. But surely this really is per definition a burnt chop? Well, possibly so, nonetheless it still tastes great!  The chances of tipping affecting your roast to the stage of having to dump all of it is quite slim.  Odds are that your chosen profile or roast degree is way off, and that tipping is only a really small part of the problem.

Scorching
So, if tipping is a burnt spot on the tip of a bean, then what's scorching? To me, scorching is bad practice. Certainly not a bad tasting bad practice, but one that points to inexperience on the side of the roast master.

Scorching happens when the bean touches a surface that is too hot for the thermal conductivity of the bean. Exactly 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 reduce steadily the ramp-time of your profile to negate any scorching. You ought not need certainly to scorch the beans to achieve your chosen roasting profile.

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

Here's what scorching looks like:

Scorching
Photo Source: www.perfectdailygrind.com

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

Crating
Photo Source: www.fullcoffeeroast.com

What's the clear answer?
If you choose that tipping, scorching, or cratering is the reason for any unwanted flavours in your bean, here's what direction to go:

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

Scorching: Lessen 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 in the form of hot air as opposed to a hot drum.

Cratering: Increase the full time from first to second crack and take a gentler approach will assist you to prevent cratering.  Dial back on your own gas pressure once you reach first crack and allow 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 this case, the whole bean is splintering apart because of your requirement for 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 any or all Genio customers, where he discusses common roasting defects in depth. Click on the link to see this specific module.