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Identifying Extraction Defects in the Coffee Puck

Video Transcript:

Hey guys Joel from Artisti Coffee Roasters. In the espresso bar, back behind the coffee machine. Today we're going to be talking about extraction defects and helping you hopefully understand a little bit more about what's happening during the extraction process to get a better cup of coffee. So it's fairly accepted in the specialty coffee industry now that most people are using what we call brew ratios or brew recipes. This is kind of something that hopefully standardizes the taste of coffee between cafes and also it helps you get the most out of your cup. What we're going to look at today, is I suppose the next step above that. A more advanced way of looking at extractions and hopefully work out

what's happening inside our extraction by analysing our puck afterwards and hopefully using some techniques to get the most out of that. There's a few things that we need to cover off before we get into it. Really most coffee machines are really doing the same thing although there might be small adjustments. Don't get me on the technicalities of that. When we put our coffee into our handle here we're going to tamp that nice and flat level. Put it up into our coffee machine as soon as we press the button the coffee machine is going to pump 94 degree water, 93, whatever you've got your coffee machine setup. Pressurized water 9 bars onto that bed of coffee. The big thing to understand is, if there's any

imperfections in that bed of coffee, any weak points that pressurized water will find the least path of resistance. So if there's a hollow air bubble in your puck when you tamp it then the coffee,  sorry the

water when introduced to that coffee baby's going to find that. If you've

cracked the seal around the outside of your basket the coffee will run around the side of your puck and not run evenly through. The ultimate goal that we're trying to get to is the water to run from the top of the puck all the way to the bottom consistently the whole way through that coffee.  If that's not happening you're not going to get the true flavour of the coffee. You're going to over extract parts of the coffee, while under  extracting other parts. It's kind of a weird concept when you

think about it but it can make a huge difference to the taste of your coffee. It'll also help you in understanding how to best achieve the brew recipes that are given to you as a barista and maybe avoid some issues that you would have had in the past or may have in the future. Hopefully you learn a bit from today. So today I'm going to demonstrate, I suppose

poor technique and good technique and show you how that can really affect the cup of coffee and help you achieve the brew recipe that you're after. The brew recipe that I'm going to be using today is twenty-two point five grams of coffee in. Which is our dry coffee. Forty five

grams of extracted yield. Which is our wet coffee underneath and I'm going to be trying to aim to do that in 36 seconds. Let's give it a go I suppose. So I'm just dosing 22.5 grams of coffee. Spot on and I'm not going to distribute this very well. I'm just going to put it straight into the basket okay. As is and use my trusty Puq Press. We’re in peak service here we've got no time to muck around. So we're going to get into it. My

coffee machine is preset for these buttons to extract 45 grams each time. Now the coffee is starting to come through. One thing that I'm going to be looking for in my extraction is to see a nice even colour progression. What that means is starting off dark turning to a darker

caramel a lighter caramel and then blonding. All happening progressively at the same time. What I don't want to see is that extraction going really, really light very, very quickly and also seeing

a really dark, I suppose lines coming through. That's a key indicator that you're getting channelling in your extraction and you're not getting the most out of the coffee. Okay so that extraction that we did there that was 30 seconds. Okay so it's quite a ways under my goal extraction time of 36 seconds. Let's have a look at this puck here. Okay great it's worked. It's done exactly what I wanted it to do. You can see with this puck here that we've got those wormholes or channelling happening. That's where

there's weak points in the bed of the coffee and water has run through very, very quickly. The other thing that we can see is around the edge here,  the seal is broken between the coffee bed and the edge of the basket. That means that water has run around the edge of the coffee

and not evenly runs through. The other thing that I can do is just use my

finger and press on the coffee and I can actually feel that there is

inconsistencies in the density of the coffee. Up here I've got a big air pocket when I press on it. It pops back down very, very quickly. Over here is a really, really dense part of coffee. That means that the water has been running through one part where it's very weak and not running through another part. Okay,  so that's poor technique. The manual would tell you right if I'm not achieving my 36 second extraction 30 seconds to make my grind finer. Now that's true to a point but if we're getting these I suppose defects in our extraction, making the grind finer, although it will slow the extraction to a point it's not going to be enough. It's not going to help you too much. What I'll end up doing is getting more defects in

my extraction through having those tight fine grind and the other thing is

depending on what briny you're using there's a good chance that you're going to find trying to achieve that goal and possibly block up your grinder. So what the one thing that I'm going to change, I'm not going to change my dose in. I'm not going to change how fine the grind is. I'm going to change my technique and distribute the coffee a little bit better.

So there's a few different I suppose tools that we can use to help us distribute the coffee a bit better. There’s things like the OCD and other products, distribution tools on the market. There's a good old dosing tool.  One thing that we do have as well is the bench that we can use in our finger. So, this part of it I'm doing exactly the same grind, same dose. So, again I'm just going back up to 22.5 grams. When I turn it over I'm giving it a big shake. What that's going to do is it's going to break down any boulders or any clumps that you have in your coffee and make it

really nice and airy. The next thing I'm going to do tap it on my bench that will compact the coffee. If there's any weak points in the coffee it will collapse any air pockets. The next thing I'm going to do is just use my finger to evenly distribute the coffee around the basket. Okay, so you can see there I've got a nice smooth flat even bit of coffee. Using my Puq Press exactly the same as before so it's all controlled.  I haven't

changed any grind settings those settings or tamp pressure or anything

like that. It's only been the distribution that's being different. So again extracting my 45 grams out as per my recipe. Now let's see what effect

this has actually had on the extraction. You can see that was a more viscous, drippy extraction at the start and hopefully the progression of the colours through the extraction happen evenly and I'm not seeing those dark lines through a very light caramel extraction. What you'll also find is the point of blonding will be pushed later in the extraction and all of those particles in the extraction will extract evenly and more consistent. Okay great so we've actually extracted the same amount of coffee using the same preset button, used the same dose in, used the same grind particle size, but we've been able to achieve a 38 second

extracting through better distribution. Now when I pulled my first extraction, remember that was 30 seconds and my goal was 36 seconds. I haven't changed the grind, everything in the manual tells you

to change the grind. I've distributed the coffee better and I've been able to increase the extraction time by 8 seconds not only have I increased the extraction time but I've also improved the way that coffee has extracted. I've got better flavours from the coffee. I've got a more even progression. There's going to be more complexity, more depth in the coffee and when we have a look at the puck here you can see that there is no channelling. There is no crack between the bed of coffee or the puck and the edge of the basket and again when I'm using my finger it's nice and evenly I suppose dispersed around the basket. It's nice and soft and consistent with no air pockets in it.  So, the big takeaway from this today is grind particle size is definitely a big thing, but good distribution technique can be the difference between you know a 30 second

extraction and that 36 second or goal extraction that we're after. It also

changes the flavour of the coffee vastly and allows you to get the most out of your coffee. So, next time that you're setting up and dialing in your grinder take those things into consideration and look for those grind defects and use a good distribution technique to hopefully

get the most out of your extraction.

Hope you enjoyed watching. Please if you want to see a video about

another subject or something that you're curious about or if you've got any questions put them in the comments below. Make sure you subscribe to our page and we'll see you next time.


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