Hi, I'm Neal Wilson with Wilson's Coffee & Tea
and in this video I'm going to demonstrate a procedure
for developing a roast profile.
So what is a roast profile anyway? A roast profile is just a record
of how a coffee was roasted. Most importantly,
that tells you what the bean temperature is
over time. How hot is the coffee at any given moment?
You can also record other information on that.
If you have access to the temperature in other parts of the roaster
such as the air temperature the exhaust temperature
you can have those in your roast profile
as well. Those are not necessarily things that you'll want to
match on future batches. It's not as useful as the bean temperature but
it can provide some additional information that helps you
match that bean temperature. Similarly you might have access to the control data
such as
fuel settings, air flow, there are also roasters
that have color meters built into them so you can tell what color the coffee
beans are at any given time and that can also be
useful if you have it. So how do you
create a roast profile? There are a few different options here.
You can record the time and temperature
at just a few key points: perhaps just the temperature
that you drop the beans at, where it bottoms out,
and a few key points such as when chemical reactions start to
occur, first crack, second crack, when you're ending.
The benefit of that is that you have a very compact
record of the roast but you also don't have a lot of detail there.
another approach is to record the temperature data at regular intervals.
You might record the temperature every 15, 30 seconds.
Do that very regularly throughout the roast.
Another option and what we're going to be using here
is automated computer logging. With automated computer logging you don't
have to worry so much about the mechanics
of creating the roast profile. You can focus more on
the act of roasting itself.
With the software we're using here, all of that roast
profile data goes into a database that makes it much easier to keep track
of what you're doing over time. It lets you easily
pull up the information on any given batch of coffee.
So why use a roast profile? A big reason here
is consistency
when you have a roast profile you can duplicate that profile
creating the same bean temperatures over time as your target profile
and that will help immensely in
getting the same coffee on every batch
you can also have some additional checks on the consistency keeping track
of percent weight lost, bean color
cup character, things like that.
simply using a roast profile gets you consistency
now that might be consistently good, it might be consistently
awful, but every batch is the same. You develop a roast profile
to get quality. What is the best way to roast
this particular coffee? So we're going to start roasting
this coffee. What I have here is a
very nice coffee from Bolivia.
So we enter the green coffee we're using,
the weight of that coffee
and now we're ready to start our profile development batch.
Toward the end of this batch I'm going to pull several samples and
these are going to be identified by the
letter B and a number. We can set that up in our data logger.
Several minutes into the batch we can see what's going on in our data logger.
On the top with your most recent set of measurements. I have two thermocouples on
this roaster so I can read the bean temperature and the air temperature
I also have the time since the start of the batch. There's also a table view that shows the
time, bean temperature, air temperature
and control annotations. I have that set
to show one measurement every 30 seconds plus
any measurement that's associated with an annotation.
That can be adjusted to show more or less data. We also have a graph view of
the data as it's coming in.
The lower curve here shows the bean temperature
and the upper curve shows the air temperature.
Since heat transfer is mainly from the hot
roasting air into the coffee bean the air temperature is generally going to
be higher than the bean temperature.
What exactly those temperature measurements are
that's going to vary from roaster to roaster and it's going
to vary depending on how well
the probes are placed, drum geometry, all of that can
have an effect on that.
Now we're ready to pull some samples. What I'm trying to do
is get samples across a range from lighter than I'm looking for
through darker than what I'm looking for
and with this particular coffee I'm looking for
two roasts. I'm looking for one
good medium roast something that
has a particular flavor characteristic that
my customers are accustomed to for this
particular coffee and I'm also looking
for a darker roast something where you can clearly tell that this is a dark roast
coffee but you can also still tell that
the coffee comes from Bolivia.
So here I'm marking in
the data logging software when I start pulling my samples.
and I need enough of each sample
so that I can cup these later. You'll note that I'm not particularly concerned
with cooling these beans.
because in a real batch it does take some time to
cool the beans off. With these smaller
samples the cooling can happen much faster.
so I'm going to pull all of my samples
and when I'm done with that I'll shake the coffee beans and that will get them
cooled off in about the same amount of time
as a production roast on this roaster.
now we can see the data that we
collected.
We have 12 samples here and the data is saved
for
future recall.
Next we need to cup all of these samples. And you'll note that
I'm not using a cupping form here. By the time the coffee gets to this point
we should already know
that the coffee itself meets our quality expectations.
We're really just trying to figure out how to roast
the coffee.
so I'll taste all of these samples that we've pulled. So what I'm doing here is I'm just
picking out the samples that
I like, what meets the criteria that I'm looking for
in terms of a roasted product what I'll usually do
here is try all of them once
then try them again and pull out the ones that might
be good and then as the coffees cool I'll narrow that down
further, tasting the ones that were good, see how they act as they
cool off aand through a process of elimination eventually we'll pick out the coffees
that I want to replicate
so considering the lighter of the 2 roasts that i'm looking for
I like sample 4, I like sample 5
and these are really very close to each other
so I'm having a little bit of a difficult time picking between them
and this is really just going to come down
to how well they perform as they cool off.
and it turns out that sample 5 was really nice
and we also have a sample 10 that was
that was very nice on the dark side. Now here we found
a couple really nice samples that we wanted to duplicate
but that doesn't always happen
sometimes we'll go through that and find
that we need to make some changes to the roast profile
a lot of this is based on experience you might know that
changing the air flow on your roster does a certain thing and that that might be
beneficial for a particular coffee
The other major change is
adjusting how long you spend in
certain temperature ranges. Having an understanding
of what's going on chemically during the roasting process can really help
with that
if you know where certain chemicals are being synthesized and where those are
being broken down
that can really help in targeting those changes
for a coffee I'm less familiar with I might do multiple batches
all up front to see how different parameter adjustments will
affect that coffee. So here what I'm doing is defining in our database
of roasting information
a roasted coffee item
We've had this particular mark in the past so I'm just going to
take that out of the list of discontinued items and put it back into
the list of current items.
Now I can enter in the details of the batch.
The roasted coffee item,
the
green coffee that I'm using, how much coffee I'm
using for this batch and once again we don't
have a target
roast profile
set up so we'll click
the no profile button
of course we do have that roast profile information. It's
just in a different
place so we'll load an additional roast profile as our target
pull up the sample batch and load that as our
target roast profile and
there it is
and here what I'm going to be doing
is trying to duplicate sample
B-5 from that
data so we won't be going through all the way. We'll
stop it once we're
done
so here I'm keeping an eye on the data that's coming in, what the current bean temperature is, what I'm shooting for in my
target roast profile, trying to keep the controls nice and
steady, trying to match up with
our target profile as best I can
After several minutes this is what we see in the data
logger. We have our target roast profile information in the table
and on the graph just as before
but we also have new columns in the table with our
current data as it's coming in. We also have two additional lines on the graph
showing the
current bean and air temperature. I'm trying to match the bean
temperature as closely as I can
The air temperature I don't really care about
these were different sized batches
as we can
see the initial temperature was much
hotter those air temperatures are
not going to match up.
but they do help me make control adjustments to keep the bean temperatures lined up.
On this particular roaster chemical changes aren't happening until the beans hit
300 degrees Fahrenheit so the temperature readings
that we're getting
before that point don't really matter so much. That's why I'm not
worried about the higher starting temperature or the higher
turnaround temp.
As the roast progresses though we see that the temperatures line up very
nicely with the target profile.
So at the end of the roast we can see that we did a pretty good job. The bean
temperatures are lining up very well with the
target roast profile we hit the same end temperature at the same time
It's not really realistic to expect to get much closer than that.
So now that the batch is done we enter our roasted weight
that gets us a percent weight loss and since I'm happy with how we replicated
that batch we can go ahead
and save that as a target roast profile and we won't have
to see the extra data from our initial test batch
when we want to duplicate that in the future. Once we're done with this
I'll take that coffee and I'll brew it as a customer might
That gets me a final approval on that roast profile
results from the cuping table don't always translate
to a normal brewed coffee so we do want to make that check and make sure that
what we're doing really is going to taste good for the customer
this is also a good time to record any
quality assurance parameters that we might be interested in
these are very similar to
those checks on consistency that were mentioned earlier
We'll record the percent weight loss some places will also record the color of the
bean
there are machines that will measure the color of a coffee
there are also color tiles that are available that are not quite as precise
but are much cheaper. The other thing that we're interested
in keeping track of is what does this coffee
taste like? Here again we don't
necessarily mean a cupping form, we're just interested
in what are the important elements of the flavor of this coffee
here again we've already determined the quality of the green coffee
We're looking for more of a qualitative analysis
that we can use for future batches
Does this coffee taste like the coffee that I roasted last week last month
and so on? and with that we've developed
a target roast profile.