Degassing & Backflushing
Hello, everyone at Unspecialty Edu
Latte art class is back again
Today, we are going to talk about espresso
The questions I often receive while doing latte art is
How does this art stay on for so long, what's the secret?
And I think there must be something wrong with my espresso because it's impossible to do art on them
So these are some of the questions I heard
So I think it'll be much helpful if we learn about espresso extraction
before we go any further
The beans I brought today is only 2 days old since it was roasted
So the beans are quite gassy
So it's way too gassy to use like normal beans
But now I'm going to show you how you can use that
and how that can help with the espressos you have
Let's check it out
Alright, are you ready? Let's go
The coffee beans I will use today are a blend with more than 80% Robusta
It's only been two days since it was roasted
I've prepared this bean today as it's clearer to see the gas in
the crema layer of the espresso
Let's look it after extracting an espresso
The grinder I'm using is Anfim SP2 grinder
After tamping, what is backflushing exactly?
And why do we use it?
The basic principle of backflushing is to push water to the back and clean the pipe
When we clean, we usually use the blind basket
So if you look here, when we clean
We put the cleaning powder in and attach it like this
I have a separate cleaning button. But if I just do it myself
When it's turned off, the water overflows backward, and the
residues inside there gets cleaned
But if we use the ground coffee, the coffee
will act as a lid and blocks it
So it enables to blow the gas backward
If you ask why we need to do that
When it encounters hot water and causes a chemical reaction
Gas comes out to help with smooth extraction
But there's too much gas layer in the middle
So the water has to push out the gas too, making extraction very difficult
So we roast the coffee beans and let them rest for a certain period before using them
That's called degassing, and we do it for that reason
But when we have to use beans that have been recently roasted due to unavoidable circumstances
We can use backflushing function
However, when I want to finely adjust the taste or scent
You should definitely check the taste after extracting this
I don't use strong-scented beans either
Because there might be scent trapped in the gas layer
So you can use it in unavoidable situations
And when I practice latte art
You may use beans that are old or the ones that were roasted incorrectly
or Robusta could also be used
So here's how to make adjustments at such times
And for you to see
I'll demonstrate latte art with the Arabica beans we use at the cafe
Keep watching so you don't miss out
Now, I'm going to extract this bean the normal way
Without the backflushing
At work, I use bottomless portafilters that has no spout
But this time, I'll be using one with it
The reason why the extract comes out in drops
Is because the extract is coming out while pushing out the excessive gas from inside
So it is very slow, thick, and sticky
25-26 seconds have already passed, but the amount of extract is only this much
The reason we use a scale when extracting at work
Is because though it may seem like a certain amount, most of it could actually be layers of gas
The scale provides the weight, which helps in uniform extraction
Now I have extracted for about 53 seconds
And if you look here, there's an enormous amount of gas on the top
If you take a look on its side, you can also see the layers
This particular shot was extracted without backflushing
I didn't turn it off and on during the process
For the second one, I will do a backflushing when extracting the shot
Let's see what difference it makes
I also get asked
So when exactly should I turn it off?
While observing the extraction process, there's a point in time when gas starts to come out
That is when you know gas has been generated from within
That is when you turn it off, but instead of turning it right back on
Wait for about a second before resuming the extraction
The longer you wait while it's off
You can expect having a more diluted form of the extract
Let me do this once more
The coffee grind is set to a certain amount, so I will use an equal amount
First is leveling
I'm using PUQ Press Auto-temping
So the same amount of force has been applied
This time, I will do a backflush at the point when gas starts to come out during extraction
Extraction is very important because espresso always comes with variables
When the gas comes out, get rid them, then resume normal extraction
Let's look at the extraction form
You will see that the extraction is much smoother
That is because I blew away the gas layer in between
So it is a lot easier for the extract to come out than before
I'm going to extract a similar amount to what we has before
If you look here, the surface will rise as time passes
The two can be compared at this point
Even to our naked eyes, you can see
A much smoother espresso has been extracted
I will do another extraction, and this time
To emphasize the degree of impact,
I will try backflushing 3 times
By this method, I will blow off as much gas as possible on the crema layer and extract it
To reiterate, having too much gas means
It's similar to the thickness of milk froth
So if I try backflushing 3 times,
then it'll give that thinner milk froth, right?
Shall we take a look?
I'm really glad I can actually show you how this works
as you can clearly see the difference once you take a look
You can see whether my espresso contained a lot of gas,
or needed more time for degassing,
These are the things you can check for
For example, if you took an order for a latte
if bubbles rise in the brown part, the brown part of the crema layer,
it means there is a lot of gas in the crema
If bubbles rise in the white part, the milk,
Think of it as having a bit of bubbles in your milk froth
You should start with the simplest part
This time, I'll try backflushing 3 times
There won't be any cases in a cafe where you make an order after backflushing 3 times, right?
We will do this to visually spot the differences
Now the water has been absorbed and it's starting to come out
Because gas is generated inside, I turned it off once
And then I extracted it. The extraction came out fairly smoothly, but
I'll turn it off once more, release the gas, then try extracting it again
Do you see how the extraction is much faster than before? Let's try it once more.
Then it will be similar to releasing all the gas in that was inside
It comes out smoothly just like water
The crema layer is almost non-existent in beans that have been roasted for a long time
Because over time, gas has been completely released
Let's extract it like this and compare
As time passes, gas will gradually rise and the layer will have enough thickness to be visible
Think of this gas layer of the espresso as
a certain amount crema layer
Because when fresh coffee beans are exposed to heat
The small beans that were once green in color
change to brown and expand in volume.
As the volume expands, the holes inside become slightly larger,
gas fills up inside
So if you put the coffee beans in a bag right after roasting,
the bag will puff up in the same manner.
Because over time, they release that gas,
When we open the puffed-up bag, the aroma comes out strongly
But if we leave it open without sealing it
Now, after all the gas has escaped
coffee oil may leak out
If more time passes, the oil may spoil
If you extract coffee using that bean, a stream of water will pour out from the beginning
This is because there is no gas layer
So depending on the degassing time
it affects the taste of espresso
So when I use it in the cafe
I usually degass it, but if I'm too busy
and there are not many beans left that I have to use the ones that are still quite fresh
Then first, you need to check the taste
How much the gas has an effect
If the taste is significantly different, I would quickly open the bag
or I would grind it a little in advance
I would put it in a slightly warm place to speed up the degassing process
I will use it after doing those processes
If you see this, you can see this one is very thin.
You can see the height of the gas layer that was there
This one is in the middle, and this one is the thinnest
If you look at the tone, this one has the brightest color
You can see, it even affects the contrast of the crema
You can check this just by backflushing
If you do it unnecessarily more, it will be useless
Let me zoom in on this part once more so you can see it better
First, I will try extracting without the backflush
If you look inside the spout here,
You can see that the gas keeps coming out
It comes out really thick and sticky
I like thick espresso, but
If there's too much, it just becomes too excessive
It can taste like powdered grain
Even though it has been over 31 seconds, the amount of extraction is still
Due to the gas, the extraction is not smooth, so the amount is not much
Let's extract until about 45 seconds
When it reaches this point, there are a lot of remaining gas on top
Look at this
If you see here, the surface is very rough
Even if I move, it's very thick
You can see the thickness and the spots
Even from the side, the gas is very thick
To compare it with this, for the second espresso extraction
Let's only do one backflush
I'll try backflushing once
Wait and watch the extraction
pause for about one second when gas starts to come out and do the backflushing
It's not completely without gas, but
The extraction is way smoother than before
Because it blows away the gas layer between the coffee beans and the hot water a little bit
It’s better. I will extract a similar amount and turn it off
Now, if you take a look at this, look at how glossy it is
And if you look from the side, you can see the crema layer is starting to rise a little bit
You will be able to see the thickness
It's currently rising
If you compare the two glasses from the front
The first is just a mess, a complete mess
If I were to compare espresso to the surface of the skin
We need to go see a dermatologist here
But look at this. The glossiness and look how nice it looks
But let's compare with one more
This time, let's compare with the one that
had been backflushed 3 times
If you look, you can see this crema layer has a much thicker texture
You can also see that it looks good proportionally
This time, let's try backflushing for 3 times
Wait for the first drops after the water is absorbed
After the drop, backflush and pause then extract
It's coming out more smoothly than before, but
Let me do one more backflush to blow away the remaining gas
It still comes out very quickly
There is no need for further backflushing, but for comparison
I will turn it off once more and try extracting
Why I'm showing you this is to
show you the reason we roast and allow for a degassing period
If you look at it from above,
It has a much smoother texture
Because we can say that it has been extracted more clearly
Because the crema itself contains gas
If we based it on the thickness of the crema
Right now, this one deflated after having so much gas
making it look like some sort of volcano eruption
To make this gas more stable
Because I backflushed too much gas at once
Even til now, it's still glossy and when seen from the side
the ratio of the espresso layer is nicely distributed
And I mentioned that this is what I am currently using
After three backflushes
The tone of the crema layer itself is very light now
It is very clear, and there's color difference when seen from the above
When making latte art, the espresso has this much influence
in contrast to its sharpness
You've witnessed espresso extraction by backflushing. How was it?
It is clearly visible with your eyes, right?
The reason why I froth my milk in a glossy and velvety texture is because
this espresso becomes the canvas for my art
and if the surface is smooth and is in good condition
The art can come out even more beautiful if both are met
So, we do this process to control the crema
But what you need to remember is
For beans used in cafes, it's not that backflushing is necessary
But you need to know the state of the espresso crema well
So, if it needs a little more degassing, you can open it in advance
so the extraction comes out smooth therefore you need to pay attention
to your milk and espresso so you can create more beautiful work
is the main point of today's class
And because I also run a cafe myself
Why don't we compare using the latte arts made by the Arabica coffee beans I have
and the beans we use for practice
Will Arabica beans work better for latte art or not?
Or would the beans made for practice be better for latte arts?
I'm sure that's something you are all curious about
In fact, beans with better contrast have better sharpness
Therefore, it'll turn out more beautifully
But even with good ingredients
If you can't fully express the sharpness in latte art,
the result would be bad even when compared with the latte art made with not that great materials
So it's important to practice with the basic principles in mind
Good ingredients have better clarity
Whereas if the color tone of the espresso is weak, the clarity can be slightly low
But it doesn’t mean that the latte art would not work
So let’s go over it together and check it out
Let's go!
Prepare two pitchers with milk
I have about 300ml of milk in it now
and I’m going to draw a picture in an 8-ounce cup
When I froth my milk, I adjust the amount to fit this cup
and some of you asked me about that as well
But the reason I do this way is because in fact, I participate in a lot of competitions
and in competitions, there are designated cups
The sizes of the cups are all different like this
So when I participate in competitions
I steamed an adjusted amount of milk to fit the cup
but there were variables in my milk
So I practiced by fixing the amount of milk for steaming
In your case, you could practice adjusting the amount of milk
to match the cups used in your cafes
So you don't have to do it exactly as same as me
But I’m telling you this since it will be helpful when preparing
for competitions later on
So now I'll show you how I make latte art using the
beans for practice purposes
Like I mentioned in the previous extraction,
I'll backflush it once before using it
Press extract. You would know about steaming if you have seen the previous lesson
After finding the center, place the cup and tilt it to the right.
Do a backflush once
hear the hissing sound,
Up 0.1, another 0.1, and up again for another 0.1
After doing this, check the temperature and then turn it off
Adjust the amount and let me try with practice beans
Let the milk flow and land on the surface smoothly,
Move sideways, go down, go up, and move a bit while standing still
Then a rosetta swan like this would be drawn
Now, I'll try it with the beans we use in our cafe, the Arabica coffee beans
Like I'm serving my customer
With this one, there's too much gas and the coffee beans are mixed right now
So that's why I used the one with a spout because there is an extraction deviation
But just like we do in our cafe
This one is bottomless. It doesn't have a spout at the bottom
Because I can see better how the channeling moves
and since the other one is too heavy, I prefer this one
So if you look here, this is what we use for lattes
This is the Arabica beans we use in the cafe
Because it hasn't been used today
I'll remove the leftover coffee grinds in the first doser
I roast and use coffee beans in small quantities as needed
so this one is not heavily aged yet
Let's try it
When should I start steaming my milk? When should I start to get the timing right?
Is some of the questions I get asked
The start of steaming your milk depends on the speed of the espresso
So I adjust the speed based on how it's extracted
Listen to the sound of that milk steaming
Lifting it by 0.1, again, 0.1, and once more. After steaming the milk like this
I’ll transfer the espresso from the shot glass to the cup and I'll adjust the amount a little
This one still has a bit of gas, but let me try it out
Mix it gently
Gently going down and up on the crema
and staying at the same spot so it creates a head, and it's the same rosetta swan as before
If you look at it like this, there may be a difference in the overall tone of the color
As I mentioned, the contrast between Robusta beans and Arabica beans
May have a noticeable difference, but the latte art comes out the same
The wine-colored cup I just showed you is the cafe latte beans currently being used in our cafe
So, I feel that those beans could benefit from a bit more aging
But actually, it’s not a matter of whether the latte art will be successful or not
Because there is some gas in the espresso extraction
If it degasses a bit more,
It would become a better ingredient for mixing with milk
And when tasting it, looking for the flavor you were looking for
can also be difficult if there is too much gas
as it can slightly affect the tasting as well
And the reason I showed you those two now is because
Arabica is also a very good ingredient
There is no problem at all in creating a beautiful latte art
And the reason I showed you
was just in case some of you were worried about having
a light espresso
If it is an espresso with a tone slightly lighter than this
If the beans are slightly brighter
Then only the color becomes slightly lighter
And to express a specific pattern, especially a difficult one
Espresso can have a greater impact, however
practicing the latte art here in this class
or at the cafe or even at home
Most beans are fine
If the beans are too old or too fresh
I wanted to mention that it might have a bit of influence
We have to learn up to here for me to really
pass down my method for making latte art
It seemed to be good to clear up some doubts about espresso
Which is why I made this session
Then I will see you in the next session
Thank you