There seems to be a massive misconception between tipping, scorching, blowing, and burning.. Part of the problem is there is no naming convention – does “roaster” make reference to anyone or the equipment; is “dropping” taking the beans out or putting them in to the drum? Is “tipping” and “scorching” the same and just how do we spot the difference?
Well, I don't know who decides on the exact naming conventions, but here is my take on it:
Tipping
The phrase “tipping” almost certainly identifies the phenomenon where the “tip” of the bean burns black. Which makes sense to me, at least.
Just how to “spot” Tipping
Tipping happens once the beans experience any temperature too high for the bean's heat-transfer coefficient. i.e., there is so much energy (heat) around a particular area of the bean that the bean cannot absorb/conduct/disperse the vitality fast enough. The sole choice left would be to burn in that area.
An example are available in just about any kind of meat grilling. A simple lamb chop on the grill has tipping across the edges. coffee roasting business This is brought on by a lot of heat at any one time, causing the meat to char instead of cook. This is often what are the results to the beans: there is a lot of heat for the bean to occupy, so it burns.
What causes Tipping?
So, when does tipping occur? Truth is that we don't know exactly. The meaning above tells us that it can happen anytime, whenever the temperature is too high during the roast. It can happen because of too high a charging temperature (the starting temp), too high a ramp during roasting…a lot of heat anywhere!
The following question is whether this 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 just a factor of the beans, not the environment, the roaster, the drum, or air temperature. The fact is that the coffee bean cannot handle it.
Look at the image below:
The colours show the difference in temperatures within the beans. It is clear from the image that, if anything should burn, it would be the tips of the beans! But this changes depending on 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 effectation of Tipping on you roast?
So, is tipping a poor 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 just a bad thing! May be the “tipping” on the lamb chops a poor thing? No, most of us love 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 level of getting to dump it all is very slim. Odds are that the chosen profile or roast degree is way off, and that tipping is just a tiny area of the problem.
Scorching
So, if tipping is just a burnt spot on the end of a bean, then what's scorching? In my experience, scorching is bad practice. Certainly not a poor tasting bad practice, but one that points to inexperience quietly of the roast master.
Scorching happens once the bean touches an area 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! Try a cooler charge temperature or reduce the ramp-time of one's profile to negate any scorching. You should not have to scorch the beans to attain your chosen roasting profile.
Scorching is distinctive from tipping in that it typically presents on the flat side of the bean. It is just a larger spot that is burnt black.
Here's what scorching looks like:
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 within the beans is released at this kind of high rate that the bean's surface cannot handle the release. This is per definition “second crack”, but in case of cratering, the next crack was induced so much that it affects the structural integrity of the bean and literally blows an item off once the bean releases the built-up gasses within the bean.
What's the solution?
If you choose that tipping, scorching, or cratering is the reason for any unwanted flavours in your bean, here's how to proceed:
Tipping: Lower your charge temp and perform a slower, gentler roast. Increasing your convection heat must also help, in addition to increasing the batch size and drum speed. The most effective is always to roast longer and gentler allowing your beans enough time and energy to absorb and distribute the vitality that you want to force into them.
Scorching: Lower your charge temp and raise your drum speed. The less time the bean spends quietly of the drum, the less scorching you'll have. Try to increase your convection heat and minimize your conduction heat, i.e., transfer your power by means of hot air instead of a warm drum.
Cratering: Increase the full time from first to second crack and take a gentler approach will prevent cratering. Dial back on your gas pressure once 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 cases like this, the entire bean is splintering apart because of one's 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 Genio customers, where he discusses common roasting defects in depth. Click the link to see this specific module.
