Here's another video explaining just a little bit more about the IMF Coffee Roaster which we use and how it compares to a more traditional style drum roaster such as the Roastmax featured here. As Luke explains in the video the major points of difference are how heat is transferred through to roast the coffee beans and also how that heat is controlled. We hope you're enjoying the insights into our roasting equipment and thanks so much for watching!
Unedited Video Transcript
the difference between a traditional
drum roaster and an imf hot air drum
roaster
stick about and i'll talk you through it
[Music]
g'day luke here from artisti coffee
roasters welcome back to our youtube
channel
where we guide you through all things
coffee now if you love our channel make
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answer them
so today we're talking about the
difference between a
standard drum roaster and the imf we're
going to be covering
the technology behind the heat source
and how that actually gets into the
beans
so when we talk about roasting coffee
beans there are two main principles of
heat transfer
there is convection and conductive so
the conductive is when the bean itself
actually hits the outside edge of a drum
and is touching that and it is receiving
the heat because that drum is metal
and it's hot that's the same as a
sausage on a barbecue that plate is hot
the sausage touches it and essentially
it cooks the sausage the other is
convection
and that is the environment that a bean
is floating around in
that has a heat source to it essentially
or a higher temperature
that we can adjust throughout the
roasting so
in roasting we do actually have the
principles
of convection and conductive at the same
time
but we want to be able to control those
and the biggest difference
between a traditional drum roaster and
an imf
hot air roaster is that there is far
more control
and better air flow on the convection
side
rather than the conductive side so let's
go and have a look at what traditional
roaster looks like
so i can explain this further for you so
this is a conventional roaster and i
just want to point out a few
of the items that actually make it work
so what we've got down here
is a fan motor which is actually going
to
suck all of the air out of the heated
beans
we've got a motor that's going to be
running the drum here and we've got a
fan motor
at the back we have our chaff collector
in here we have our burner
and then we've got our controls on the
front here so
what this roaster is doing is
essentially
in under here we've got a big gas burner
you know an upgraded version of your bbq
burner essentially
and you can see that there is a drum up
under here and it's providing a heat
source straight onto that drum
and that will heat up over time and we
can modulate the heat
on that actual flame from this gauge
and just by using a dial so you can
increase the heat at the start and we
want to really start getting some energy
into that beam
and as we taper it off towards the end
of the roast we would be decreasing that
heat so that it doesn't burn the beans
too quickly and
as far as the that is the conductive
side of the roasting
so where does the convection side come
into it it's all from this fan here
and what it's doing is trying to suck
that heat up through the back of this
drum which actually has some
perforations in it
it's pulling air through the beans as
they're jumping around in the air from
the
basically a mixer inside the drum a
couple of big paddles there
and it's coming up through this top
chamber through this tube
and we can then modulate that amount of
air so we can either close it right off
and a paddle will come across and stop
that air from being sucked in
or we can open it up fully or halfway
whatever we choose
and essentially that's taking the excess
heat back to our chaff collector
and then out the exhaust so it's quite a
easy way to have a heat source and
produce a good
environment for beans to roast in that
we can actually change
from our roasting from start to finish
so that's how drum roaster works so
let's go take a look at the imf
so from this side the imf roaster looks
quite similar
it does have our front hot plate the
drum and this entry level
for beams to come into but it's not how
it actually gets its heat source
like the other roaster now if you want
to know more about this whole roasting
facility check out our other video we'll
leave you a link
let's go around have a look at the back
here and we'll talk about the heat
source and how it enters this drum
so this is an afterburner now a lot of
roasters don't have afterburners
but essentially what it is is a big
burner that is running at about 600
degrees
and usually it's used to condition the
smoke
and the odors from a roaster so that
when it goes into the atmosphere
you don't get any smell and affect your
neighbors essentially
but what imf does here is actually
injects this heat
very clean beautiful air into the actual
roasting drum
so if we look up here we've got a tube
and you can see this pivot point that is
a really big
paddle which essentially will open and
close allowing the heat to actually go
straight into the roaster
now we don't want to put 600 degrees
heat straight in
so underneath here there is actually an
air inlet
and i can actually feel the actual
sucking coming up through
these pipes because there's an
atmosphere outside
so cold air is being sucked in here and
it is mixed with the hot air
and it is then pushed in through as you
can see through the back of the roaster
here
so it comes down into this tube so it's
going straight into the beans
and this is a temperature probe and
basically we are asking
this roaster to deliver us a certain
amount of heat
at any time throughout the roast now
that could be
600 degrees it could be zero degrees and
it will just continually to modulate
through this here
which is called a vortex system so we've
got a huge amount
of um heat source on demand at any time
we'd like
it's just uh we've got to ask it just
give us some heat gives it to us
so it's very effective it is a huge
amount of massive heat that we can
inject straight into those beans
that's going through the actual beans
then that heat would be
residually being on the actual drum
so it's going through beans and outside
the drum the heat
that heat then actually gets reticulated
back through the roaster
and i'll show you that on the other side
so the heat is then
coming through this drum and then out
through
into our chaff collector and that's
where all that fine particle or
husk will actually end up through this
little bag at the back here
now that extra heat will actually then
go back
inside through this tube and back into
the afterburner
so it's a full reticulating system which
makes it very effective for
creating a heat source and then there's
very little waste going out to the
atmosphere
so there's a good overview of how the
heat source works on an imf roaster
now the guys at imf actually have an
amazing video that can show you
digitally where the heat sources come
from and how they go through the roaster
so
we'll leave you a link below so you can
check that as well
and what i wanted to cover one last
thing is this
is an imf roaster that is a drum roaster
that has a hot
air flow or hot air
source so look there are hot air
roasters which work
very different again but i really wanted
to make it clear that this is not an
underneath style gas flame burner trying
to heat a drum with that huge
conductivity style heat force so i hope
you've got something out of this video
if you've got any other questions please
shoot us a comment we'd love to hear
from you thanks very much guys
have an awesome day
