deeply into the weeds of science. So, this is going to be one of those
segments where there’s tons to glean, lots to learn, so don’t feel like you’re
going to be able to capture all of this in one segment. If we run long i’m going
to feel for a natural breaking point and we’ll chop it down into manageable bites
for you. Before we get into first crack, Joe and I have just returned from
Roasters Guild, that’s part of what I’d like to discuss. Then, we’ve got a
commercial, so Joe reactions? As what are you president of the Roasters Guild?
the chair of membership and communication so I get to talk to
members and help with what gets put on the website, what content we put out
there, and stuff like that.
content, build content, give to your community, find out what happenings are
going on around the country, be supported in the events that you put on, be
supported in the small groups that you may have around the country, or around
the world. We are a global community, so
in Australia are gonna bounce from
walking away with four for intense days with roasters all the way from mom and
pop shops, novices, all the way up to a huge unnamed coffee company that
everybody would recognize.
getting ready to talk to talk about, all the way to cupping notes and theories
about roasting with people that are brand-new and people that have a PhD in
biochemistry and in–
machines. I don’t want anybody to think I’m too small for something like Roaster Guild. Really fine organization. My wife said, what are you, how do you
understand this weekend? I said this is continuing education. Coffee is one of
those fields where unless I’m learning something that particular day, my boss
should fire me.
it’s kind of like riding a bike. As soon as you have no more momentum you are
falling down, so we should always be learning all of us.
Steve wants to talk about Twitter and Instagram. This is @RoasterJoe, we are
@MillCityRoaster and we’d like to follow you. So shoot us an email, what I’m most
interested in is to have a friend capture a picture of you at your roaster so
that we can follow you. So we’d love to to build that social content because
it’s moved from more than advertising to where information is shared on social
more you’re able to exchange ideas and exchange your findings, as you’re
roasting coffee. So it really does create community and camaraderie.
of information to be shared. Something novel, that’s either discovered or
obscure that coffee roasters would do. I also post about baseball as I know
Joe does so any baseball fans, follow Mill City Roaster, Roaster Joe, or Bold
Java, we’d love to have you follow there.
working with Joe and building segments of a roast. We’ve been talking apart about charge
temperature, we’ve been talking about charge size, we’ve been talking about
turn around, we’ve been talking about the drying
phase of coffee, and Joe is going to talk about first crack so Joe this forum is
yours, my friend.
a lot of stuff to get through. It can be very, very complicated. I am not going to
complicate this, but rather i’m hoping to simplify this as much as I possibly can
and we’re going to, we’re going to start kind of simple they were going to get
very complicated, and then were going to come back down to hopefully being very simple
again. So hang with me and know that if you don’t have the time to sit down and
watch through an entire episode it’s cool…there’s this wonderful feature on
the internet called pause, so you can watch a little bit pause it go back, go do your work, come back at another time, mark where you stopped. We want you to
take your time and digest these things. Also, understand i’m not a scientist so a
lot of the things that i’m talking about here are things that I’ve learned in a
similar way to how teaching them so if you are a scientist you know some of
this stuff more in-depth, or better than I do or a way to explain it that I
am not explaining it, please reach out and let me know because
i would love to bring that to the forefront. I am not the end-all be-all
authority on all things coffee so–
will feed them in as Nick sees an appropriate time and place in Joe’s
going to have a disconnect I want to teach based on what you do
want to know and what you are needing to know. Ok. Alright so I have the title here
called: browning, first crack, development. These are all terms that we use within
coffee kind of in a general way. The way that first crack has been adopted into
our lexicon has been almost like this moment where–it’s like a magical moment,
and then everything that happens prior to first crack is just building heat,
everything that’s happening post first crack is something called development
where we were where we are building flavor and I have to say that that is a myth and I
want to talk to you about why that’s a myth. What’s happening when and what
importance first crack actually has to us and this term development, what
does that actually mean? Ok? So we have those two stages of
roasting: the first stage from the time that we have the charge to the time that
our coffee is yellow, once again is something called endothermic. It’s an
endothermic reaction where we’re absorbing heat and remember this is
actually a myth, as well. We’re actually moving ever forward with momentum that’s why i have the dotted line here, ok. so coffee starts at the room
temperature from which you got your bag of coffee and put it in and then it’s
ever moving forward at a curve. Ok, so as this coffee is moving forward
it absorbs heat, all of your free moisture leaves the coffee, and at that
point when you start seeing some browning reactions that is where you are
beginning what I would call development. You are now changing chemical compounds in the coffee into flavors. So there are a bunch of different chemical
compounds that are within the coffee. ATP is a type of energy that is stored
in the coffee and that ATP is broken down by the coffee plant in order to
energize that plant. Within a seed, it’s stored in a way that that seed, when
activated with water and in the ground will begin breaking it down okay. The plant uses a system called
hydrolysis. Hydrolysis is where water is kind injected and pushed into the
molecule and it cleaves that molecule into different molecules. So if you have
a large molecule of cellulose, for instance, you can use the process of
hydrolysis to create something called cellobiose. This process, or this compound through which hydrolysis happens is called cellobiose and then you can break it down to glucose, and of course
glucose we know is a sugar. Ok, this is not what is happening within
roasting. I hear a lot of times people talking about about hydrolysis and
roasting, that’s actually not happening. That’s not the chemical reaction that we
want to focus on. This is what happens in beer though. If you have that that grain
you allow the grain to germinate and the hydrolysis process breaks down those
starches into more simple sugars which are then soluble and which, of course,
bacteria like to eat and burp out their gases and they make alcohol. However,
we’re going to look at different reactions that are taking place. Now
there are some people who have projected that early in the roast, prior to
yellowing, there is some hydrolysis happening because we’re adding energy to
the seed and that seed has water in it. Hydrolysis has to happen with water
present. Once we’ve dried that coffee out, though, the water that is present is
being manufactured by these processes of dehydration which are dehydrating
molecules–were breaking those molecules down. Ok, so let’s focus mainly on these
reactions. Ok, the maillard reaction starts taking
place when we move out of yellow and we start seeing browning and we start
smelling aromatics that are telling us that that reaction is happening. That is
this list of things that I have here: ketones, furans, aldehydes, esters, phenalics, terpenoids, thiols. All of the– and there are more, these are all actually categories of
different types of aromatic compounds that are created when we are roasting
coffee. It is incredible. Underneath all of these
we could list a whole bunch more. Ok, so now if I’m if I’m roasting my
curve and I see that my curve is going kinda flat, or my curve is going kind of steep, or
my curve is perfect, and it looks like the Mona Lisa of all curves–guess what
it doesn’t really matter. Doesn’t matter. I could stare at this curve all day long,
and it’s not really telling me anything about the taste. Because at different
kinds of heating, at different strengths different powers of energy
that we’re pumping into that coffee, we can use that energy to cleave these base
molecules, these large molecules into a whole range of potential aromatic
compounds. So if my curve is flat on one coffee, it may make a certain type of ketone, if
my curve is sharp on another coffee that may be what’s necessary for that
particular molecule to make the same kind of ketone, for instance. It is so
vast and so in-depth molecularly and chemically that with our simple
tools there’s no way to measure it. Actually with very advanced scientific
tools there’s no way to measure exactly how our molecules are going to break
down. That’s why bringing this back to a very
simple answer to all of this you have to taste the coffee. If you’re looking at
your curve and you are just driving hypothetical ideas of whether or not you
roasted the coffee correctly based on how a curve looks, you have no idea what
is actually in the coffee, ok. Furthermore, if you look at something
like, let’s just take ketones for instance, ketones are category of
aromatic compounds. The majority of them are associated with aromatics such as
butter, brown sugar, some of these really rich deep characteristics. However, others of these are related to
fruit-like tones. So i could even think that I’m right about some kind of compound sounds that I am creating in the coffee through a certain roasting process and I could be totally wrong about what that compound is. Adding complication to that, when you have simple sugar which is a
subset after these things have broken down these will become simple sugars
such as glucose, fructose, and I’m sorry. Glucose and fructose are
subsets of sucrose so if you have– even if you have sucrose in your original
green coffee, through these processes they will break that sucrose down into
its more simple sugar and then that simple sugar will break down very very
quickly. It’s a very fragile molecule. Fructose
molecule is very very fragile. So a lot of seasoned roasters will also say that
a lot of the sweetness that we get out of coffee is perceived sweetness, that
the actual sugar content in brewed coffee is very very minimal so those
ideas behind “I want to stay longer in caramelization in order to make my
coffee sweeter,” or, “I want to stay longer in the maillard reaction in order to
make my coffee sweeter,” that is actually a myth. You’re not going to make coffee sweeter
by breaking down a sugar molecule.
reaction. That is not going to be the result of what you’re trying to go for.
Because if you have a sugar molecule and you break that sugar molecule it’s no
longer a sugar molecule. If you have a complex sugar molecule, like for instance
sucrose is a fairly complex sugar molecule, and you break that down into its
it’s smaller sugar molecules, such as fructose, that fructose molecule will
break very quickly. And when you are using heat, which is energy, but heat energy
for these processes this is a domino effect. So it’s not like
as soon as that sugar that sucrose molecule breaks it down to fructose, that
you can then drop it out of the drum and capture that. These things are happening
well before first track, well before first crack. As you are seeing browning
in your coffee, and as you begin smelling aromatics that are not the aromatics of
green coffee, you know that these reactions are taking place and by nature
of that you’re you’re creating a chain-reaction a domino effect that will
do away with any sugar that is actually in the coffee and simplify that. Now
there are caveats to this: if you start with the coffee that has a very high
sugar content then you’ll probably end up with the residual sugar left in that
coffee being at a at a higher level. Ok, if you have a coffee that is very
dense and holds a lot of material within it then that by nature says that you
have more residual sugar at the end of your roast. Plus, it’s holding onto a little bit more
of that. There are some theories that if you take a longer amount of time, which
is what i preach with a more dense coffee, in this area that you may
actually be able to cause some hydrolysis, to use some of the actual
cellulose, which is the structural material of the seed, and go through this
process while you are in this early stage and provide, and maybe build into
the seed, more sugar than it had before you had it in the drum. Now that is
theory, I don’t know–you can do flavor analysis on your coffee and do some
experimentation. I would see that it would probably work for some it may
completely destroy others so it’s not high or, hard-and-fast rule. Ok, do you have that rope you can pull me
out of the weeds on?
Talk about the difference and talk about the similarities. I’m using them the same
because within our roasting process they are more than likely and generally are
happening at the same time. Ok, so if I have a cell structure,
there’s our little nucleus, this cell may have a whole bunch of sugar or potential
sugar in it. Ok, this part of this cell if it’s
isolated, if that sugar, is isolated and the heat starts breaking it down these
molecules are going to start breaking and they’re going to have simple
caramelization. Simple caramelization is going to happen. Simple caramelization is
the dehydration of sugars through the heating effect so as it as you have your
simple sugar and it breaks, gives off that molecule of carbon dioxide, gives
off that molecule H20, and you have now something. It actually will give off
furfuryl, which is a direct correlation to caramelization, and furfuryl is actually
a bitter compound and it’s an aromatic compounds. So whenever you say, “I smell sweetness,” you’re probably smelling something like
this, it’s not actual sugar that you smell. So this process is very simple. However, if there are amino acids present,
you know proteins, and they’re generally are within coffee, there’s a lot more
going on in that cell than just sugars hanging out, then you have the maillard
reaction. And the maillard reaction is– I put plural here on purpose– it is a set, it’s an umbrella that covers hundredsand hundreds of different kinds of reactions. Because, for instance, if you
have one type o f sugar with one type of amino acid, that those two will come together and
depending on the arrangement that they come together at you can have several
different reactions and the result of that could be several different compounds. Now, extrapolate that to coffee. With coffee, we are starting out with about 300 or
more volatile or potentially volatile compounds within the green coffee itself.
So the way that those react, that’s an exponential equation, the
way that those react is basically incalculable onto our ability to sense
exactly which reaction is happening in which style, at which time. We can’t do it.
So that is why I kind of crammed these together, because there is so much going
on there’s no way to know whether this is happening or this is happening and on
our probe of course we could say that the maillard reaction happens at this temperature to
this temperature, but our probe is not giving us exactly what that temperature
is at this cellular level at any given moment.
particular amount of flame, or heat exchange that’s coming from the air.
coffee are gone. Ok, roughly 320 to 340 degrees.
because there’s more bean mass around the probe. The probe is further away from
the from the drum wall, so it really varies. But no matter what this
temperature is, that doesn’t matter. What matters is on your drum where does it happen? And how long has it
taken to get there? Or on your air roaster or whatever you have, and then how long is
it going to take you to get from first crack–or from this to and through first
crack? So now let’s talk about first crack. What is first crack? First crack is
not a magical point at which the coffee now begins to go through a certain type
of change. First crack is a reaction to all of these things happening. So as
caramelization happens, you have your simple H20 and your simple carbon
dioxide breaking off from that sugar. That’s why a lot of people say that
first crack is a release of steam pressure. But it’s not just steam, all of
these other things are volatile compounds that will break off of a
molecule. Some of them will be stored in the seed and some of them will not. When
you grind your coffee that beautiful aromatic expression that you get from
coffee is these that are captured in the air, because they are gas, there now in the
air and you’re smelling them. Ok, so as maillard reaction and
caramelization happen, new molecules are created that are inflating that seed, you
will have first crack. That’s why it’s really foolish of us to look at
everything after first crack as being development because if we rush
up the first track and then slow it down, we may have just missed all of this time where all of these things could be developed in the coffee. Ok, so that is why it’s really important
for us to pay attention to all stages in the roast. Look at these marks as
milestones, as transitionary points where you can measure time, but that is another
reason why i use thirty-second increments to measure my time is because
I know that that will give me a closer snapshot as to how my curve is
developing. Now, i just got done saying don’t sit there and study your curve, study your curve, study your curve. Sure, draw your curve, cup your coffee, then go back to your
curve cut 20 different roasts, 20 different curves, cup them all. See which
one has the expression of that coffee that you like the best, and then work
your way backward through that curve starting with that time from first crack
on, that has traditionally been “development.” I want to kill that word, I
just want to call this “Post First,” Okay?
we are browning. But browning happens all the way through. Ok, it continues to happen until you’re
into blackening, ok. So browning would be at yellow that is an actual physical
change where you’re converting from one type of energy change to another. You’re
converting from endothermic to exothermic.
Exothermic there is now chemical change and every point where you have a breach
of a compound, every point where you take a sugar and you break it, there’s a tiny bit of energy that is
actually released so at that, when you go into exothermic heating–you are actually
creating energy. You’re using energy to cause the reaction and then you’re using
energy to make sure that that chain reaction continues to happen. But, that is
actually creating energy at the same time.
because again first crack is a reaction, first crack is not the action, it’s a reaction. So if I have, here is a
another very key point I want you to think about, if I have some of this moisture
left over, hanging out when I should be going through these, if
in this cell there’s a bunch of water just kind of hanging out, that water is
quenching these reactions. I cannot have maillard reaction if I add water. I cannot have caramelization if I add
water, and if you’re holding onto a lot of water in your drum or in your seeds
then you are preventing these. Now there are theories out there, and again this
may be a point where you stop and listen and now you’re going to start again,
there are theories out there that you can stall your hydrolysis, or you can
stall in this part, so in other words your curve would kind of flattened and
then come back up– so a curve kinda like this–
you can kind of stall these from happening and then you can slowly let
them happen so they don’t go too far and you hold onto more sugar. I would say
that that is a theory that I have not had very good success with. Some roasters, you will have some more success with. This is what I would call a Diedrich
curve on an IR roaster or maybe even a roaster that has a lot of heavy metal,
like for instance cast iron. Cast iron doesn’t really have good heat exchange,
it holds onto its energy instead of giving its energy away. So on a cast-iron
roaster, or a more conductive type of heating you’ll see this but convection
really helps to get that moisture out of the way and allow you to go through
these reactions. Ok, that’s why if you’re going through
these reactions if you if you hit these reactions too fast then you’re just
going to blow through all this stuff. You’re going to burn that out. If you hit
too slow then you’re not going to really develop all of the flavors you might
cleave those compounds down, but they’re not going to break into a bunch of
fragmented, you know, diverse characteristics in that
coffee. So you’ve got to find the sweet spot for every coffee, and how do you do that? Not by getting more and more technical
equipment, not by getting molecular sniffers that are sniffing every single
cell in the coffee. Of course, my nerd brain wants to have something like that
so that I can control exactly what compounds on making at which time. But at the end of the day, at the end of the day, none of this matters, ok, to the point
that– remember our analytical tool, our analytical tool– does it make you
happy? Ok, so all of this is very complicated,
all of this you need to know these things are happening because this is,
this is going to help you realize that watching that graph and only paying
attention to this is really distracting you from the reality of what’s happening.
And the only thing that you really need to know is does it taste good? And can I make it taste better? And where in here do I go back to to get that taste that I
had before on that one roast that was perfect that one time. why did that happen? Ok, was it during the maillard reaction stage? Or was it something, you know, uncharacteristic
about that coffee that day, what was it?
without cupping is immaterial.
the exact amount of grams, exact amount of water, you need to go through a
systematic cupping. That will help as you grow your business, to have its
systematic. But if you’re using a brewer, if you’re using an espresso machine,
whatever you are roasting for– if all of this is for espresso then you
probably shouldn’t use a cupping bowl to make these analytical
decisions. You should probably use an espresso machine. But taste, taste, taste, record, taste,
record, record your roasts, record the things that are different, especially
that’s why we look at first crack because it’s a mile post, it tells me of
a specific moment and I can correlate a specific time and temp to when that first
crack happened I can draw a box and I can mark that out, and if that box is bigger
another time if I went further in time for another first crack those two
coffees gonna taste different. It’s a good difference? Is a bad
difference? Well, if I never measured where first crack happened I don’t know
how to go backward so measure all of your milestones, measure your time over temp, and go back to that information after you have tasted the coffee.
start with coffee about 10.5% water.
we get to the yellow phase how much water is left?
water we’re getting rid of most of the water.
could be the case that we are getting rid of the free water but we’re already
starting to create more.
activity that that creates, that drives all the chemical compound changes that
you’re talking about here.
top of the sponge if that sponge is dry and you put it on a burner you won’t
feel any heat on the other side of sponge. If that sponge is wet and you put
it on a burner, that water will pull heat from the burner to the top of the sponge.
It’s conductive. So if we can use this water while it’s around to drive energy into the center of the core of bean so we can get all of these the reactions to start taking place in a
uniform way, then we can control those reactions a little bit more and by
“controlling” I mean recreate the same roast each time we want to go back and
roast it. So we’re just setting ourselves up for success by using that water.
instead of browning?
sense of it, as a roaster, is I’m moving into a convective phase and I need that
air to drive that convective energy, is that correct?
that a convection oven will bake your bread faster than a conventional oven
will bake your bread. A convection system for coffee is more efficient, if
you are air roaster you know this. You’re done with your coffee in six
minutes, it roasts very very quickly. You can easily skip over some of these reactions
though, so having a little conduction having that convection to back up that
efficiency of energy in a controlled way gives you exactly the outcomes you want.
learn as you were roasting on the units up at PT’s?
focused on the sensory side of coffee, so we didn’t like sit down and break down
exactly when–is maillard doing this, is carmelization doing that?– we didn’t sit
and study all of the profiles and in judge, oh I think your profile was a
little high here, or a little low there. We went to the
cupping room, and we cupped. So the biggest learning curve is learning how to taste,
and being calibrated with not only your team, but everybody in coffee. So
calibration, tasting, and figuring out when I taste this in the coffee, I know
that I need to go back and look at this in my profile.
than just yourself.
all will submit coffee and we’ll taste those coffees and we’ll evaluate for ,you
know, how those coffees are tasting.
evaluating cupping, whatever you want to call it, I found for myself that I learn
more within a group that we were able to build on one another’s knowledge
exponentially rather than just me drilling down on the table every Friday
afternoon. You put three or four people and they don’t have to be serious, they don’t have to be coffee experts, but
they do want to learn. They do want to grow together, so I really encourage guys,
people if you’re serious about tasting, evaluating, moving along your palate for
sensory determination, do it within the group.
hope that you have opportunities to kind of go back through and and listen in. If
I said anything that is wrong or weird or something, please revisit it with me.
I’m happy to learn and admit where I am wrong.
that I slept through biology both in high school and college,
to be doing some reading on the carmelization, simple sugars, complex
sugars. I’m going to be reading about carbohydrates, and their interaction with
water and heat. I’m going to be reading a little bit
about maillard, if I remember correctly he was the father of French food science, is
roasting and understanding it a little bit differently. All that’s the way of saying, for me,
there’s a lot of meat here to chew on. I don’t expect to absorb this in the the
24 minutes that Joe covered it. But, it’s time for me just to take three or four
nuggets out of here and build on them.
Joe fields all the equipment and all this plant physiology and physics and
thermals and all of that stuff. And so we’ll cover that in Roaster School in
September. The 30th of September, 2 p.m. Central Time, Joe will lead a group of probably six professional
cuppers, six professional coffee couple people here – six professional coffee people here in
town through the seven finalists in our Focus on the Roast. We had 115 applicants this year.
out those packets of 10 pounds each yesterday so they’re on their way to the –
at Mill City Roasters, as well as Cafe Imports. I think that’s a wrap. Joe, good
session, my friend.
instagram – love pictures of your photos. Thanks for watching it.