Roaster School Online – Ep #1 – Turning Point
Tags: and, that, the
Roasters, along with…
representatives and also the director of education and you may see me at Roaster
Guild events as well. I’m on the Executive Council of the Roaster’s Guild.
a look at our own videos, Joe and I discussed it, and we’re moving to a new project, Roaster School, where Joe is going to help us take a deeper dive on
roasting segments. We want to give you the science, the principles, and the
application behind roasting with your coffee roaster. Joe is going to be telling us items that
are going to help you with whatever manufacturer and the roaster that you’re
working with so whether you’re on the North or a
Deidrich those principles and science and application will help us improve our
coffees. Joe thought we’d start out today with turning point. Joe uses
another term for it…
your roaster and those greens drop down on their migration north so without any
further ado, Joe, how about it?
coffee if you would like however we found that a lot of times i
would get distracted by roasting or distracted by a question or trying to
of only focusing on one thing really well at a time and shorting the other So today we’re going to focus on only
one thing; and that is teaching you about the turn around. So the turning point is that point in
which when you drop the coffee into your drum you see your temperature if you’re
graphing a temperature stop and turn around so this point right here. I feel like
there and I hear a lot of misconceptions about what exactly is taking place here.
So I really wanted to get into the nitty-gritty and start with this and
then in our consecutive classes that we’ll have together we’re going to move
along the chain of how the roast develops.
roaster out there?
collect your temperature data. If you’re collecting your temperature data I guess this is the first step, you want
to have some kind of chart system. Whether it’s an actual graph that you
are charting out on paper or whether it is a system of boxes where you’ll have
your chart like this and then you have your temperature change and you
have your time and you can just write each one into each graph line. Can you see how wonderful I draw?
time is it and what temperature is it and then you can write that on a graph
so this would be your temperature and this would be your time.
forward, but your temperature is going to find a particular place along that graph.
So whenever you put your coffee into the drum, what is happening is: your drum is at a
certain temperature. Generally on most drums, you’re somewhere in the range
between 375° and 425°, okay? It depends on your probes, it
depends on what size drum, and it depends on how hot you want that drum. Okay? So let’s just pretend this is 400,°
because that is a general range – okay? At some point, when you add in the
coffee you’re going to see the coffee is then
going to pull against this temperature and it’s going to pull it down and then
they’re going to reach an equilibrium but I don’t want you to think about it
and being like your coffee is 400° and then it drops in temperature
and comes back up. This – all of this information right here – All of this is actually noise – it’s not
real. Okay? What is really happening is your
drum is at 400 degrees and your coffee is at room temperature, okay? Whatever temperature your coffee was when you put it into the drum. And what’s really happening to your coffee’s temperature is it is moving upward – ever marching upward from the time that you
put it into the drum. Okay. Unless you do something and it
happens to fall stagnant along the roast somewhere, which we don’t want to have happen.
But it’s ever marching upward, okay? So think about it in these terms. Now
your relationships matter, okay? In life and in coffee. Your relationship between the
temperature of your drum, the temperature of your coffee as you put the coffee
into the drum, the size of your batch – so how much does that batch weigh? – and the
density of your coffee, ok? So if I have a drum that has the
capacity for – just for our sake let’s say… well what size drum you want to work
one-kilo drum – and i’ll explain that density here in just a moment a little bit more in depth. So here is a
1 kilo drum, and I’m going to put in about eighty percent capacity, which
capacity this equals 2.2 046 pounds, so let’s say we’re going to shoot for
eighty percent. Let’s just say we’re doing – let’s just say .8 kilos. Okay, and then you can divide that number
out at home for fun. I’m not going to do it in my head. So you’re putting in your eight – your
.8 kilos okay, and that .8 kilo is starting at room
temperature – let’s just say 75 degrees, all right? If
your drum has been sitting at 400 degrees for 20 minutes, 10 minutes – if
it’s stably at 400 degrees – then your turn around on that coffee at .8 kilos if all of these things are the same, that
turnaround should be the same every single time that you roast that coffee.
If all of your variables are the same. If your airflow is the same, if your gas
is in the same position, if it’s the same coffee, if it’s the same temperature of
your drum, same temperature of your coffee, and same weight. If something changes for your coffee,
then you know that there is something off. Something is off somewhere.
Generally what I see is people are turning their drums on and trying to get
to this temperature far too quickly, because they think that they need to
drop at 400 degrees. So you get the drum up to 400 degrees,
and then you drive your coffee in. Well that doesn’t work, because your drum
hasn’t fully absorbed all of that heat and held that heat at that temperature. So even though your probe may be showing
you that you’re at 400 degrees, the drum is still on its way of
catching up with that. That 400 degrees is only at that site where you have your
temperature probe, and the rest of the drums still needs to get hot, okay? Now, this is where it starts to get
a little complicated, is when you change which coffee you’re dropping this amount. What I
recommend for you if you are new to roasting is use your full charge, which
is generally .8 or eighty percent of what the roaster manufacturer says
the roast is, because this gives you a lot of leeway to turn your gas up and
not flatten it out. If you start with a full load and you get behind, you don’t
really have the momentum to get that forward for where you need to go. So I do
recommend starting at about eighty percent capacity, and then I recommend with
all of your coffees try to keep that same charge until you really understand
the fundamentals of your roaster. So then if I take another coffee, and
that coffee is more dense – which what I mean by that is, every seed weighs more.
So whenever you weigh out your .8 kilos, you’re actually weighing out less
coffee. You’ll see in the, in the bucket that you’re weighing it in, it’ll be stunted.
It will be a little less, will be less material. So what that means is is two things. The
first thing is, in your drum.. This is your drum. Your drum has these
things that fly off of it that toss coffee about, right? As your drum is rotating, let’s say it’s
rotating this way, your coffee is collecting, and your
coffee will start collecting actually collects right up here. Okay? But it’s also tossing about, tossing
about, tossing about. If I have less coffee in that drum, the mass of that
coffee is going to be more diffuse in that space, so the dense coffee is going
to come in contact with metal and other coffee seeds less often. Okay. That also means that my coffee seed
is going to dry out a little bit more quickly on the outside, because it’s
exposed to more air that’s taking that moisture off of the coffee. So what ends up happening also along
with that, where my probe is, wherever that probe is in that drum it’s getting hit by less coffee, so it’s
showing that my coffee is actually having a smaller effect on this number, okay? So if it’s having a smaller effect, that
means that it’s going to change the way that that temperature is corresponding
to my turnaround, okay? So it it may show you that you are turning around more quickly
or most slowly depending on the density of the coffee
that you’re putting in there, because the mass of .8 kilos could be any
number of beans. It could be two million beans, it could be 1.5 million beans. It
just all depends on your roaster. So you want to think about on how these
things correspond together. So if you are changing your coffee, it is very important for you to
understand where your turnaround needs to be for that particular coffee. And I
can’t tell you you need to be at a hundred and seventy-five degrees
Fahrenheit on your drum for this particular coffee, because every coffee
is going to have its own turn around temperature. So let’s
simplify this. To simplify this and not get caught up in the weeds of all of
this, it’s very important that you keep track
of your roasts, okay, that you pay attention to your start
temp, that you pay attention to your bean’s temperature, your coffee’s temperature, that you try to
keep track of a very thoughtful and consistent batch size for whatever
coffees that you’re using, and then pay attention to where that coffee naturally
wants to turn around at a general drop temperature. So instead of messing with your coffee
and saying, “Well, I’m going to do, I’m going to do sixty percent batch today, and I
think that I need to then lower my charge down to 395 and then try to find
out where my turn around temperature was whenever I had a point, you know, or an eighty percent batch at
400,” that’s all out the window. Even though
you’re turning around at the same temperature, by pulling all
those pulleys and levers and making that happen, that doesn’t necessarily mean that a
minute, two minutes, three minutes down the road you’re going to be on the same
path. Okay, so keep these things as consistent as
you can until you fully understand how each coffee is turning around, okay? If your coffee is turning around more
quickly, then your coffee is probably a little bit less dense. It’s going to take on the heat more
quickly, and it’s going to move through the roast a lot more quickly. If your
coffee is turning around a little bit later, then your coffee is probably a
little bit more dense. It’s not taking on the heat as quickly, and that’s okay. A lower density coffee needs a little
bit more time to absorb that heat, both because of the structure of the coffee
and because of the nature of how that coffee is in the drum, okay? So your more dense coffee is going
to pull harder against this, and it’s going to drop down further away. This distance is not going to be very
significant, but it still matters. And why does it matter? Well, if first crack
happens at a particular temperature, which it does, then if this is five
degrees lower, then it’s going to take you that amount of time to get to first
crack. It’s going to be a longer roast
automatically, and you want to make sure that you’re not rushing it as you’re getting it out of
your turn around. So the way that I look at this, and you’ve heard this analogy
probably before, is this is kind of like a launching pad
to the speed that your roast is then going to move forward. And so if your
coffee is coming down on this launching pad on too hard, then it’s not going to
be able to pull up out of that turn around. If your coffee is coming down and
getting stopped before that launching pad, it’s going to just blast off, and
it’s going to take off very quickly. Okay, any questions?
your roaster. Time after time after time, use that same charge size. Joe’s talked
about most of the roasters out there – sweet spot about 75 to 80 percent. For
those of you that are on North your full charge size should be one kilo. It’s not down in the eighty percent
range. It is a full kilo or full 500 grams. That’s one thing. Joe, would you define
density? And you say one has low density and one has high density, what does the density of a coffee mean?
balloons, and they’re both the exact same size, that is your mass. If one
of them is filled with water that’s your density. It’s a lot more dense. There’s a lot less
space in the balloon between molecules, okay?
that that coffee has stored into itself. So it’s not water, so – I know i used the
balloon analogy with water – but in a coffee, you could have a coffee that is
eleven percent moisture, they could be the exact same seed size, but one may
weigh more than the other because it has more densely compact carbohydrates, you know, all of the other sugars, all the
other things that go into that coffee seed that you’re going to turn into
flavor. The moisture is kind of insignificant as it pertains to the
density of the coffee. Moisture is kind of static. so the actual compounds that you’re
going to be converting into flavor are what build up the density of the coffee.
And if i remember correctly what you said, denser beans, where that cell
structure is tighter, are going to turn around at a lower point than coffees
with a lower density.
that in terms of that coffee starting at 75 degrees or your room temperature, then
your roaster has to do more work to get that dense coffee to move forward in it
through its heating process. And again that’s because it’s more diffuse in that
space and because those denser seeds need more energy in order to get to the
same place. If you think about this in terms of
movement, if you have a car that weighs a lot and another car that doesn’t weigh a lot,
and they have the exact same engine and the same amount of
fuel moving them, that very heavy car will take will move much more slowly
with the same amount of energy applied. So again you’re starting here
with your coffee, so if you have a very high density coffee, it’s going to take a lot more energy to
move it forward. Now automatically that makes me think from like a physics standpoint, then that
means I should be at 410. Or that means I should be hitting my my throttle
harder. Instead of being at four inches of gas i
need to be a 5 inches of gas to get that moving. Well if you do that, you’re going to
scorch your denser coffee. It’s going to burn the outside without that heat
getting a chance to penetrate. That’s why I say no matter the density,
while you’re learning the process of learning your machine and learning that
coffee, try to start with a consistent
temperature here, a consistent temperature here, and a consistent weight.
And it may be the case that eventually you get to a place where instead of
using a weight n, you’re using a mass n. So like a particular size on
a graduated cylinder of some sort – that could be the case, but the geekier you
get with all of these things, and the more you start going down rabbit holes, the more likely you are going to miss
the forest for the trees, and you’re going to get into the weeds, and if you
just pull back and keep this stuff as simple as possible and then see how
your coffee roaster responds, and then you respond to that information in a clear level-headed way, you’re going
to get a much better result out of your roaster.
you use that? Okay, it’s a piece of information. Now that
I have that piece of information, what do I do with it?
that you’re collecting should result in one piece of data that is the most
important data. Okay, and that is… does it taste good? Does it make you
happy? At the end of the roast is it an aesthetically pleasing roast? So all of
this stuff is pointing to this. And how do you know whether or not all of this
stuff matters, is by tasting it, by sharing it with friends, by sharing it
with coworkers if you’re in a professional setting. Taste, taste, taste, okay? So then when you’re
starting with all of this and as we’re going through the next segment of our
classes over the coming months, and we’re covering more and more of this chart,
then when you get to this and unfortunately it’s a little bit more
like this, then you can go back down the chart and you can find exactly the point
where something went wrong. But if I’ve changed this, if I’ve changed this, if I’ve changed
this, if I changed air flow if, I’ve changed gas if, I’ve made all of these
adjustments, then how do I know where exactly I need to make a change to fix
anything? I don’t. So you have to start with
something that’s very cut and dry, very simplistic, and even though this looks
very simplistic starting in this way, this is
actually very complex, and it’s setting you up for success. It’s just like you’re building a
house, and if you look at a blueprint for building a house, the basements of all of these different
houses look very simplistic, but they’re simplistic because they’re tried and
true, and we know that the structure that we can build on top of that can
diversify all different ways. But if their foundation, which is the beginning
part of that roast and the turn around, if that is in place, then we can move
forward and start getting a little bit more creative with the roast a little
in from the audience?
question that he rephrased for us. he’s saying if you’re targeting a specific
drying temp regardless of turn around temp, sorry, targeting a specific time phase, is the
idea that a lower turn around temp is now going to result in later milestones okay, or is that something to avoid? I
think you touched on this a little bit – I think just a clearer answer…
is okay if it results in this. Okay?If it helps your coffee tastes good,
then you can feel free to break a rule. Starting with a clear foundation will
help you get to that point more consistently. If you have a coffee that’s
an odd duck, that for whatever reason within this system you know that your roaster is heated and
stable, you know that your ambient temperature in the room is stable, you know that you’re roasting the same
amount of coffee, but for whatever reason it’s dropping well outside of a reasonable limit, then
treat that coffee as that coffee is responding within that system, okay? If you go and make an overadjust
for that coffee being outside of spec, and try to get it inside of spec, then
you’re double forcing that coffee. That coffee is telling you that it’s
different. There’s something different about it
that you have not experienced before. And so then by nature of that, that
should tell you “I don’t know this coffee.” But if you respond to that by saying “but
I’m going to treat it like every other coffee, get it to file and rank,” then you are
automatically mistreating that coffee. So if it starts falling out of rank, then
you need to set your parameters different. If that coffee doesn’t crack
on time, if it cracks at 10 minutes as opposed to eight and a half minutes, it’s okay. Get to the end of that roast by following that coffee’s lead, by
making your adjustments according to where your turn around temperature was,
and then make all of the consecutive adjustments to follow that to where if
normally it takes four minutes after turn around for yellow but turn around
happens at two minutes instead of a minute and a half, then go ahead and make
an adjustment and say “Now I want to have yellow or my coffee fully dried at four
and a half minutes instead of four, and then I’m going to push my first crack
accordingly.” And then get to where you can taste
it, and taste it in the same way that you taste it every other time. Make sure that all of those things, all
of your variables, are consistent so that then you can go back and you can say, “You
know what? That tasted really great. I’m happy with that roast, and it’s fine. I had
to break the rules.”
principles-bound than rules-bound when you roast.
the coffee presents rather, than coming at the coffee with a set of rules that
you’re going to govern for that roast.
clear-cut set of rules will actually allow you to be freer later on for
the coffee to kind of play with in that set, because you’ll know that it’s the coffee that’s making the change, whereas if you don’t start with
this, you don’t know if it’s the roaster, the
coffee, or you that’s messing with the system up. So
if you can eliminate variables as much as possible and get to the coffee
itself, then that coffee is going to show you where it kind of needs to go.
in the videos that we do, Dave talks a lot about cutting gas at the first minute, first minute and a half until you hit turning point. Harrison Boyd is wondering, is that part of
this thought process, does that play in? And to that same point, just to jump on to another question, how do you react to gas and airflow throughout this turning point?
minute. I do not use turning point. Turning
point varies for me – 55 seconds to a minute and ten with full capacity. And
that’s just a data point. I file that away mentally and say, “Ooh, this is denser
than I thought.” I leave the burners off for that first minute in that I want
that bean soaking in every bit of heat, because I’m trying to drive two things:
that core temperature to the same temperature as the outside, and I want to
activate the water. So I want that bean just taking in the heat, so I use a minute
with burners off. Joe roasts differently, and again we’re talking about roaster’s
preference. So turning point doesn’t govern me
reigniting the burners – time does.
roasting a coffee for the very first time, I will react to how the coffee is
turning around with the way that I turn on the gas, and that’s what you’ve seen
me do here, because every coffee that I’ve roasted here has been the first
time with the coffee and the first time on that machine with that coffee.
a profile, I’ll backtrack that up and get to the
point where I’m turning on my gas at the same point every time. But I’ve made I make an adjustment as to how high I
turn on my gas based on the first few times that I roasted, seeing where that
turn around is naturally occurring.
how much gas you’re administrating coming out of that turn.
around, then I know that the coffee is reacting to the heat in a very fast way,
and so that sharp turnaround will tell me that I need less gas whenever I charge my roast. However, if I
see a sagging turn around, then that tells me generally that I need a little
bit more gas. Another question?
drum roasters for what we’ve talked about today?
can drive the roast, air, gas – these are all methods of heating coffee. So, whether it’s electric or whether it’s
gas, it’s still energy coming from heat, so the basic principles of this should
apply, regardless of what kind of heat source that you have. The electric
burner is heating the metal, and the metal is heating the coffee. The electric
burner is heating the air, and the air is heating the coffee. So it’s just all a matter of that
particular system seeing how the coffee reacts within that
system. And if you have electric, or if you have gas, or if you’re roasting on an
air roaster, it’s about setting base parameters to
start, with your batch size, temperature of your equipment, and the temperature
of the coffee going in, and then how much gas or how many amps you’re going to apply to that coffee after that.
moisture content of the bean or humidity – how much does that affect your initial
charge temp or your turnaround point?
will go from a very humid day to all of a sudden it’s dry. What kind of change do you see in the same
bean that you’ve roasted on a Tuesday versus a Wednesday.
difficult question to address. There is the humidity of the coffee
itself – which I don’t know if that’s the exact question. I think that’s what the
question’s applying to?
air that we are in, or the environment. In my opinion, humidity is not what is making any kind
of an effect on any of this. In my opinion, it is the density of the coffee
and the density of the air. The density of the air is kind of affected by humidity. The density of the coffee is also kind
of affected by the humidity of the coffee. However, we can measure both through the
density check on the coffee and barometric pressure within our
environment. So, if you’re roasting on a small roaster
like this, barometric pressure is going to be kind
of a non-issue, and I think that it’s something that we really shouldn’t be
focusing on. If you’re roasting in a very large roaster, the pressure pushing down
on that roast is going to have a major change to how that roaster will roast. And
so that in a large roast setting will affect the way that you play with airflow, okay? But I don’t think that that applies
to anything above, say a 70 kilo drum or beyond. If you are seeing changes in the coffee due to the moisture in the coffee or the
moisture in the air, I would recommend looking at some other
triangulating data to make sure that you’re not making a corollary judgment
as opposed to an actual sound judgment. I think that baristas do this all the
time. They see that their coffee shop dries out all of a sudden, and they say
“Oh the you know humidity in the room changed, so it put my grind off.” That
is a correlation, that’s not a causation. We know now that
that is not true.
same thing about humidity in the air but now I know better.
check the temperature, check the temperature of the drum, make sure that
there’s not some other thing that is also off. And I’ll venture to bet
that there is – that there’s something else that you can draw conclusions from.
Good questions, Nick. Are there any others out there?
summarize some of the things Joe emphasized. Stay consistent on your charge
size as you’re beginning to learn that roaster. Do the same charge size time
after time after time. A lot of roasters, 75 to 80 percent is the sweet spot.
With the North roasters, do your full charge size.
that that charge size is on the high end. Like we don’t wanna, if you’re on a
one-kilo machine you say, “Well I’m doing the same charge size every time,” and
you’re doing a hundred grams, that doesn’t count to us. Okay? You’re
too small, and the variables involved there are throwing you way off.
Sorry to interrupt.
calls I get about that. What Joe discussed today, he was talking
and using software profiling. Everything we talked about, if you’ve got a five by eight card with
time and temperature and are tracking and plotting at that way, everything
applies. Turning point is a variable that’s dependent on the bean, on your
starting charge temp, and the ambient temperature in your
atmosphere or whatever your bean temp is. Try to keep these consistent until
you’re learning that roaster. The lower the turning point, the denser the bean, the tighter that cell is within that bean. If you get a really sharp spike coming at a turning point, you may have too much gas. Too heavy of a
foot on the pedal. So pay attention to the sharp turning points. What else did you want to emphasize that
I talked about today?
happy? Are you enjoying the coffee? That is the
most important thing. Enjoying the process is great. It’s geeky,
it’s fun, we can get down a lot of rabbit holes. But at the end of the day, taste
your coffee, and if there’s something wrong, and you’ve done your homework to where
you have managed everything, then you should be able to find that
variable that was off. And if you don’t, that means that there are probably a lot
of other variables that you don’t know about, so tune in to future events from us, and
hopefully we’ll go over some of that.
you all love it. Perfect. Hold up the mic for the camera. Three, two…