There seems to become a massive misconception between tipping, scorching, blowing, and burning.. The main problem is there is no naming convention – does “roaster” make reference to the person or the machine; is “dropping” taking the beans out or putting them in to the drum? Is “tipping” and “scorching” the same thing and just how do we spot the difference?
Well, I don’t know who decides on the exact naming conventions, but listed here is my take on it:
The word “tipping” probably identifies the phenomenon where in fact the “tip” of the bean burns black. That makes sense to me, at least.
Just how to “spot” Tipping
Tipping happens once the beans experience any temperature excessive for the bean’s heat-transfer coefficient. i.e., there is so much energy (heat) around a certain part of the bean that the bean cannot absorb/conduct/disperse the energy fast enough. The sole choice left is always to burn because area.
An analogy are available in virtually any kind of meat grilling. A simple lamb chop on the grill has tipping around the edges coffee bean roaster machine. This really is due to too much heat at any one time, evoking the meat to char as opposed to cook. This is often what goes on to the beans: there is too much heat for the bean to use up, therefore it burns.
What causes Tipping?
So, when does tipping occur? Truth is that we don’t know exactly. The definition above tells us so it can occur at any time, whenever the temperature is excessive through the roast. It can occur as a result of excessive a charging temperature (the starting temp), excessive a ramp during roasting…too much heat anywhere!
The next question is whether this is due to convection or conduction heat? Put simply: may be the drum too hot or may be the air too hot? The clear answer is: either. Tipping is really a factor of the beans, not the surroundings, the roaster, the drum, or air temperature. The fact is that the coffee bean cannot handle it.
Consider the image below:
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 will be the tips of the beans! But this changes depending on the bean: try finding tipping on peaberries. Because 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 for you roast?
So, is tipping a poor thing? That is a concern only the drinker can answer. Allow me, as I cannot stress this enough:
TASTE YOUR COFFEE!
Put 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! May be the “tipping” on the lamb chops a poor thing? No, all of us love only a little char-grilling on our chops. But surely this is per definition a burned chop? Well, possibly so, however it still tastes great! The odds of tipping affecting your roast to the point of having to dump everything is extremely slim. Chances are your chosen profile or roast degree is way off, and that tipping is a very small part of the problem.
So, if tipping is really a burnt spot on the end of a bean, then what’s scorching? If you ask me, scorching is bad practice. Definitely not a poor tasting bad practice, but one which points to inexperience privately of the roast master.
Scorching happens once the bean touches an area that’s too hot for the thermal conductivity of the bean. Just like for tipping, but almost exclusively due to conduction heat. In layman’s terms: your drum was too hot! Here is another cooler charge temperature or reduce the ramp-time of your profile to negate any scorching. You shouldn’t need certainly to scorch the beans to accomplish your preferred roasting profile.
Scorching is distinctive from tipping in so it typically presents on the flat side of the bean. It is really a larger spot that’s burnt black.
Here is what scorching looks like:
Photo Source: www.perfectdailygrind.com
There will be a lot of confusion between craters and tipping. The 2 are VERY far apart. Cratering happens near or into second crack where in fact the pressure in the beans is released at such a higher level that the bean’s surface cannot handle the release. This really is per definition “second crack”, but in case of cratering, the next crack was triggered so much so it affects the structural integrity of the bean and literally blows a piece off once the bean releases the built-up gasses in the bean.
Photo Source: www.fullcoffeeroast.com
What’s the solution?
If you choose that tipping, scorching, or cratering is the explanation for any unwanted flavours in your bean, here’s what to do:
Tipping: Reduce your charge temp and do a slower, gentler roast. Increasing your convection heat also needs to help, along with increasing the batch size and drum speed. The very best would be to roast longer and gentler allowing your beans enough time and energy to absorb and distribute the energy that you are trying to force into them.
Scorching: Reduce your charge temp and boost your drum speed. The less time the bean spends privately of the drum, the less scorching you will have. Try to maximise your convection heat and minimize your conduction heat, i.e., transfer your energy by way of heat as opposed to a hot drum.
Cratering: Increase the time from first to second crack and take a gentler approach will assist you to prevent cratering. Dial back on your gas pressure when you reach first crack and allow the beans carry themselves into second crack. In the event that you force more and more energy in to the batch, it stands to reason that “something’s gotta give&rdquo ;.In this instance, the whole bean is splintering apart because of your importance 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 or any Genio customers, where he discusses common roasting defects in depth. Go through the link to see this type of module.