HELP! What's happening to my beans?
There seems to be always a massive misconception between tipping, scorching, blowing, and burning.. The main problem is there is no naming convention – does “roaster” reference anyone or the machine; is “dropping” taking the beans out or putting them to the drum? Is “tipping” and “scorching” a similar thing and how can we spot the difference?
Well, I don't know who decides on the precise naming conventions, but here's my accept it:
Tipping The phrase “tipping” most likely identifies the phenomenon where in fact the “tip” of the bean burns black. That makes sense if you ask 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 is so much energy (heat) around a specific area of the bean that the bean cannot absorb/conduct/disperse the energy fast enough. The sole choice left would be to burn because area.
An analogy can be found in just about any form of meat grilling. A simple lamb chop on the grill has tipping across the edges coffee roasting business. This really is caused by an excessive amount of heat at any onetime, inducing the meat to char in place of cook. This really is what happens to the beans: there is an excessive amount of heat for the bean to occupy, so it burns.
The causes of Tipping?
So, when does tipping occur? The fact is that we don't know exactly. The definition above tells us so it can occur whenever you want, whenever the temperature is excessive throughout the roast. It can occur because of excessive a receiving temperature (the starting temp), excessive a ramp during roasting…an excessive amount of heat anywhere!
Another question is whether this is caused by convection or conduction heat? Put simply: may be the drum too hot or may be the air too hot? The answer is: either. Tipping is really a factor of the beans, not the environmental surroundings, the roaster, the drum, or air temperature. Truth be told that the coffee bean cannot handle it.
Look at the image below:
Tipping Photo Source: www.sciencedirect.com
The colours show the difference in temperatures within the beans. It's 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. Because the peaberries are round and has almost no distinct “tip”, the chances of tipping happening are much smaller in peaberries.
What's the aftereffect of Tipping for you roast?
So, is tipping a negative 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 a bad thing! Is the “tipping” on the lamb chops a negative 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, nonetheless it still tastes great! The chances of tipping affecting your roast to the stage of experiencing to dump everything is very slim. Chances are that your chosen profile or roast degree is way off, and that tipping is a very small area of the problem.
Scorching So, if tipping is really a burnt spot on the tip of a bean, then what is scorching? To me, scorching is bad practice. Certainly not a negative tasting bad practice, but the one that points to inexperience privately 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 caused by conduction heat. In layman's terms: your drum was too hot! Here is another cooler charge temperature or decrease the ramp-time of your profile to negate any scorching. You should not need 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 really a larger spot that is burnt black.
This is what scorching seems 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 in fact the pressure within the beans is released at such a higher rate that the bean's surface cannot handle the release. This really is per definition “second crack”, but in the case of cratering, the second 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 within the bean.
Crating Photo Source: www.fullcoffeeroast.com
What's the clear answer? If you decide that tipping, scorching, or cratering is the reason for any unwanted flavours in your bean, here's what to do:
Tipping: Lower your charge temp and do a slower, gentler roast. Increasing your convection heat must also help, in addition to increasing the batch size and drum speed. The best should 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: Lower your charge temp and raise your drum speed. The less time the bean spends privately of the drum, the less scorching you'll have. Try to maximise your convection heat and minimize your conduction heat, i.e., transfer your energy by means of heat in place of a hot drum.
Cratering: Increase the time from first to second crack and take a gentler approach will help to prevent cratering. Dial back in your gas pressure once you reach first crack and allow beans carry themselves into second crack. If you force more and more energy 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 your requirement for burnt coffee!
The Genio Academy, along 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. Go through the link to view this specific module.