roasting is a moment of truth for coffee it can either unlock the unique flavors that the producer
has worked so very hard to develop or it can reduce the flavors to generic bland and mediocre
but today i'm interrogating boris at our wollongong roastery to see his process find
out the most common mistakes and how we can avoid buying coffee that just doesn't deliver the goods
so boris let's start with the basics of roasting what is your process when we're roasting coffee
we've got two things we need to consider we've got our raw coffee seeds we call them beans but
they're seeds and then we've got our roasting machine a roasting machine generally revolves
around a drum style roaster or an airflow roaster in a drum roaster you literally have a big cast
iron drum so what happens is when we put the coffee into the drum the drum is spinning and
there's little arms on the inside of that drum and the beans roll around the drum the drum is heated
by gas burners and then the energy from that drum goes into the coffee seeds as it spins around the
drum the other thing that is happening in that environment though is we're also heating air we
are effectively roasting the coffee with both the heat and energy of the drum and the heated
energy of the air after we decide we've roasted the coffee to the point where we want it to be
we open the roaster up and we drop that coffee into a cooling tray it's really important that
this happens at the right time because when we drop the coffee out into the cooling tray
it isn't actually finished roasting at that point that's why we want to drop it into a cooling tray
and we suck air through it and we move the coffee around because we're trying to pull as much heat
out at this point because we want to lock it in at that point what dictates when you know it's
time to drop it what are the variables that are in place so a lot of roasters look at what is
happening to that seed as it becomes a roasted coffee and we follow a curve and that curve
represents the temperature of the massive coffee seeds in that drum we've got this nice hot drum
we've brought it up to a temperature and we call that our charge temperature we drop those seeds
into the drum and what happens is the temperature in that environment starts to drop because the
seeds themselves are nowhere near as hot as the drum and they start absorbing energy there is
a point where the curve effectively plateaus and starts to come back up that's our turning
point during this point we are working with an endothermic reaction okay what is endothermic so
an endothermic reaction is where we are applying heat to something and it is absorbing the heat
in this path up we get to a point where the amount of energy that is going into the seed overtakes
the amount of energy in the ambient environment and we hit critical mass and then we actually
get an exothermic reaction the opposite of endothermic and it's where there's too much energy
in that mass and it starts to escape and this is called first crack and then what happens is we go
back to an endothermic reaction where the energy starts to be absorbed again by the coffee bean
and it's during this phase of energy absorption that we have a chain of reactions called the
maillard reaction and that's what we are really aiming to control as a roaster so this is this
is the thing you're looking for when you're roasting coffee well it's a thing that happens
whenever we roast coffee um it's the same thing that happens when we toast bread or we cook a
steak the maillard reaction is the caramelization of sugar if the roaster is skilled and sets up the
environment for that development phase we set up a chain of reactions and we get a maximum amount of
sugar development so what's more important is the quality of green coffee or is it about perfecting
the roast from a roaster's perspective look i'm gonna be honest it's both but there are caveats to
that a really skilled roaster can take an average coffee and make it taste better but really you
know we are working with what we have but if we're not working with something that's really good
it is very difficult to make it exceptional when someone's starting out and roasting
what are some of the common roaster mistakes i think understanding that different coffee seeds
react to heat differently is something that it takes time you have to learn that you know
there are little tricks you can do you can buy a density checking device so that you can check the
density of your coffee seed also understanding the best way to approach the roast in your specific
roaster yep so you know when you're on looking online in forums and that you're going to see
other people putting up graphs talking about what they do if you don't have the same roaster as them
you can't just copy them you won't get the same result right so you need to learn your roaster
and you need to go back to the fundamentals of what you're doing thank you so very much Boris
for spending your time with us and showing us behind the scenes of a roaster and hey guys
anything you'd like to know about roasting next time definitely leave a comment down below and we
can look into that for a future video until then enjoy your roasted cup of coffee and stay stoked