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Watch your head space.

I’ve realised that, when I talk about coffee, what I say isn’t backed based on a data that’s been proven or experienced myself. This frustration has lead me to actually experiment on few things, rather than pondering and hypnotising myself that my pocket science (very little of it) is correct.

One subject that I always wanted to, but had no commitment to experiment, was the importance (if there is any) of headspace between the shower screen of espresso machines and the coffee bed.

In my perfect little world, I always believed that it did, that having some head space produced higher percentage of consistent shots, without any data to back my opinion on. I started to have firm believe because of several reasons, firstly, I got so frustrated when, even though I have the same dose, grind setting, extraction time and temperature of the machine in each shot, sometimes the results fluctuated quite abit. I started to dissect and see what variables I could control and those I couldn’t, I didn’t even bother about the uncontrollable variables, but I’ve realised that I’ve never accounted head space as a variable.

Those of you who use the Nuova Simoneli Aurelia ,would know that each group head has a brass dispersion block. Which disperses the hot water into 8 different holes for even distribution of water from the group head to the coffee bed.


Now this brass block comes in 2 different thickness, 3mm and 5mm ones. I first thought 2mm difference would only make a minute difference but the results below proved me wrong.

To compare and note the difference between the 2 different sizes of the dispersion block, I wanted to gather 2 different sets of data. First being consistency, and second, rate of flow/rate of espresso extraction.

So firstly, consistency:

I wanted to see the consistency of espresso produced in grams, with different size of dispersion block, when other variables become constant. (Impossible but I’ve tried my best!)

Machine used: Aurelia T3

Temperature: 94C

Time: 28 seconds

Basket: 18g VST

Dose: 19g

Coffee used: Jirmiwachu, Ethiopia SOE


If we ignore the fact that, 3mm block produced big shots that wouldn’t normally cut the mark, it is apparent from the data that, 3mm block produces fairly consistent shot in terms of weight , you have to remember that I’m just looking for consistency in weight of espresso produced.

In the other hand, the 5mm block shows that the shots produced are not even, it fluctuates rapidly after shot 4, it produces some values which could be considered as an outlier, and its hard to produce a mean value.

I’m no scientist, and I think people cleverer than me could give me a better answer, but here’s an educated guess. If we think of the shower screen as a perfume, and surface of our clothes as the coffee bed, applying perfume from a distance will cover broader surface area of your clothes evenly. On the other hand, spraying your perfume in close range will highly saturate a specific area. If we want the water to be evenly distributed amongst the coffee bed, it makes sense to me to have a gap between the surface of the coffee bed. I mean, we are talking about 93~94C water under 9bars of pressure, 2mm difference in my opinion, gives the water some space to actually distribute the water evenly.


*Note that spent coffee bed from 5mm leaves clear mark of the screw, where 3mm does not.

Lastly, I wanted to record the rate which the espresso was being extracted, by plotting a time/espresso weight graph. The reason why I wanted to obtain this data was to observe the pattern in which the flow of water through coffee bed was affected by the head space.

The result is quite interesting:

Now this graph was plotted using average values from 5 different set of shots, you can see from the result that, 5mm block produces espresso faster than the 3mm block; and that flow is maintained until 17 seconds, where the 3mm block actually overtakes 5mm block and produces more espresso at the end.

Now why does this happen? why does the flow rate gain momentum from 17 seconds on the 3mm block? Here’s my guess, the reason why 3mm block took longer to produce any espresso initially, is because the water starts to fill the basket and slowly, and saturates most of the coffee bed before extraction occurs.

Where as the 5mm block (this is just my opinion), the coffee bed is mostly pushed up against the shower screen, and when the extraction occurs, the water isn’t able to fully saturate the the coffee bed evenly and finds a path which allows extraction to occur without full saturation.

With my shallow knowledge, I wanted to know why there is an increase in flow from 17 seconds with 3mm block, and I came up with this.

Darcy’s law states that, flow rate of fluid increases as pressure increases, until it reaches a certain pressure (correct me if I’m wrong), so it would mean that there are less resistance created by the coffee bed than the 5mm block, allowing the water to flow through the coffee bed at an increasing rate, which means full saturation at the start of the extraction loosens up the coffee bed, and allows the water to flow through  evenly, which also benefits even extraction throughout the coffee bed?

I really enjoyed the shots coming out form the 3mm block, not saying the 5mm block didn’t produce any good shots, but 3mm block hands down delivered the consistency, and I think we all need that in our lives.   

The pocket science rant above could be all wrong, but having the data gives me boost of confidence in what I believe in, and I would love to hear other peoples thought on this. I would also love to be proven wrong, if anyone has better explanation please please comment!!

** For those of you without an Aurelia where you don’t have any interchangeable dispersion screen maybe try playing with different basket size, but keeping the dose same.

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How do you Americano

Americano has been on our menu as long as we can remember. Without a doubt, recent push to promote manual filter brewing has caught the customers attention, and more people are becoming aware and open minded of this new way to brew tasty coffee.
Still, Americano is a popular choice between customers- specially in recent cold weather conditions.

Throughout the day, we(hopefully) check our dose, time and yield and taste countless of shots to see if the coffee is tasting good. Embarrassingly, what I’ve noticed is that, I invest so much time dialing in filter coffee and espresso, but don’t really taste americanos.
The excuse maybe that, its too hot to taste and its not tasty, but being a drink which is quite popular, bringing money to the till, I think I or We have been turning blind eye on this drink.

Some people say if you weigh every shot, including americano, it should be fine. I know some shops who does that, I’m not saying I never weigh my shots for americano but what I found is that, with our coffee-

Type of coffee Dose(g) Time(s) Yield(g)
Espresso 17g 29s 31g
Americano 18g 31s 33g

Tasted the best, a 31g of shot of espresso which tasted good itself, can’t give you the same satisfying result when you further add 4oz of hot water or steamed milk, there should be different recipe for different types of drink.
When I tasted the americano with the shots which tasted good as espresso, It was very watery and just acidic, I know these results vary hugely on the coffee the shops use but even tasting Americanos from other shops, I know there are room for improvements.

I just wanted to share this to ask if any of you guys have a different method for pulling espressos for americanos, even though It’s a drink which gets no attention in the specialty industry, I want to make sure the 70~80 people who buys americanos from our shop gets the same tasty drink, and more attention from us making their drink as much as the espressos we pull.

Comments are welcome

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Tasty stale coffee.

One of the many joys working in the coffee industry, is trying endless amount of different coffees, in season being offered. For a year, I was subscribed to weekly and monthly coffee subscription from 2 of my favorite roastery. I’ve learnt so much by tasting different coffees itself, but what I was left with was countless amount of bags of half finished or even some unopened bags. I’m sure we all had this, but I want to focus on our customers, who buy these freshly roasted coffees from our shops.

Recently there has been substantial interest in manual filter brewing method from the customers, and beans have been flying off the shelves. If the beans were roasted on 1st of February, if FedEX does there jobs properly, it could be on the shop shelves on the 3rd of February. Now, we say that coffees taste the best when its ‘fresh’, where generally it is between 2nd day of roasting to 14th day of roasting. Now, I’m not saying it will suddenly taste horrible after 14 days, it will have so much factors affecting this, such as type of coffee, level of roast and also storage. Don’t we all agree that you can drink milk 2~3 days after its best before by dates if they are refrigerated well? Same goes for eggs and many other product.

So customers have generally, 10~12days window to enjoy their coffee whilst its fresh, if its a 250g bag thats around 21g~ 25g of coffee being consumed every day to enjoy them whilst its fresh. Presonally, if you don’t drink coffee every morning, I reckon you won’t be able to finish the bag in time, or you’ll get another subscription coffee and the old coffees are long forgotten.

So, people spend an average of £6 to £13 on bags of coffee, and most likely, they will have around 100g~150g of coffee still in the bag after 2~3 weeks, so what do you do with them? Well, there are lots of things on internet like using old coffees to use as compost, leaving them in fridge and even face pack! I wanted to find out if there are any guide lines, outlining what they can do to make decent cup of coffee using beans over 3 weeks old, rather than throwing it away. Even on the coffee bags, it states, ‘enjoy within 4weeks of roast’. So should people use the same method of brewing for all those 4 weeks? Should they be put off brewing with coffee 3 weeks or 4 weeks old?

-This isn’t a definitive guide to brew good coffee using old coffee, I firmly believe in using fresh coffee will deliver the best result in the cup!

- I will outline the changes you make to your recipe using old coffee from using fresh.

- its an experiment, and I’m not saying it will work for every coffee, as I’ve said before, there are lots of variables to take on board. - If anyone finds something other than what I state below, please comment!

- PLEASE remember, I’m NOT saying you can make the same QUALITY as fresh coffee but something you can enjoy without spitting them out, and actually drinking it rather than putting them in your fridge or your face.

So I wanted to experiment with a coffee I was familiar to, so I chose El Salvador Finca La Illusion roasted by Has Bean, because its on our shops brew menu as well as the espresso, so I know this coffee pretty well. Also luckily, I had an unopened bag of La Illusion which is 5 month old, one which is 4 weeks old and one which is 3 days old. So, I will brew these coffees, with extact amount of dose and water, time and temperature may vary. After brewing, tasting them and mojoing them, then make several changes to find that spot where the old coffees can produce ‘acceptable’ cup.

Firstly, I cupped these 3 coffees, and rated them with scale of 0~10, within different categories.

You can see from the cupping scores that 5month old coffee didn’t do so well, expected really, but surprisingly had the best body from those 3 coffees.

What really surprised me was, how pleasant 4 weeks old coffee tasted like, the only major difference between 3 day roast coffee was lack in overall complexity, but in terms of acidity, it was bright and lively.

So, I decided to brew these coffees as V60 pourover, I know I can’t brew these coffees consistently, but I tried to keep everything the same and mojo the  result which is below.

The result showed that with same dose, water, similar time and technique, as the beans that I used got older, more I extracted from the coffee. This has a correlation to the perceived bitterness I tasted from the cupping result.

With this result, I decided that it wasn’t really worth experimenting further with 5 month old beans, as they didn’t really taste good as V60, very stale, boring and bitter. These were worth going into the fridge and faces.

However, 4 weeks old coffee looked promising, it was bright, some sweetness with nice light body but had unpleasant bitterness coming through. Lacked in the complexity, exciting acidity, sweetness and the body compared to 3days old roast, but I wanted to change how I brewed the 4 weeks old roast to make it taste better and acceptable.

So this is what I’ve changed.

So, the dose was increased by 1g (6.25% increase from original dose) and amount of water reduced by 15g( 6.25% decrease from original dose).

Surprisingly, using the 6.25% increase and decrease method, When I slightly underextracted the brew, I’ve made myself a cup of coffee which was substantially better than one I made before, ok, it still wasn’t good as 3 days old roast, but there was increase in that sparkling acidity and complexity, though sweetness and body was still missing- it was an acceptable cup.

I would be interested to see if anyone experiments with 6.25% increase and decrease method I used with different coffee and brewing method, using old coffees to see if they get a positive result like me.

I know for the experienced coffee professionals, you guys don’t have to read this blog to figure out how to brew decent cup with stale coffee, again, this post is to help(hopefully) home brewers and having fun and learning myself. And please don’t  think I’m weird telling people to try stale coffee, but If you can make yourself a half decent cup of coffee when you have no fresh coffee at home; using 4~6weeks old coffee, and doing some experiments and having fun whilst doing so, I don’t see why people should be trying it. 

In this industry, you learn so much by tasting, tasting is believing!

Comments are welcome!

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Nose temperature.

One of many things I love about coffee is the fact that, the flavors of coffee that can be discerned changes as it cools. So when we are served a pour over or a syphon, we wait until its quite cool. However, recently I’ve been wondering about our nose, I find the nose really interesting, because as nose contributes significant amount to what we taste; most of the time, what we smell will taste like it. For example when we drink a cup of coffee with our nose blocked, all we can feel in our mouth is the body of the coffee, not the flavor, so no nose, no taste.

So we know that coffee tastes better when its cool, but then when can we smell coffee better?

I decided to have an experiment- to see the difference when our nose is at different temperature, and how it affects how we smell things.

This is what I did:

1. Brew syphon of Costa Rican Santa Lucia from Square Mile, and separate them into 2 tumbler glass( The reason I chose the tumbler glass is because I was able to discern more flavors of coffee, more than latte glass or porcelain cups.)


2. Just as they are decanted into 2 glasses, I go out side and start to inhale the cold air (It was 3 degrees celcius) for 1 minute so the temperature of the nose gets lower.


3. I come back in and straight away, swirl and smell one of the tumbler glass, then taste.

4. Then drink a glass of sparkling water, inhale the warm air indside(set for 27 degrees celcisus) for another minute.

5. Quickly smell the remaining tumbler and taste.

Because the experiment seemed not fair, in a sense that; I had to leave another tumbler 1 minute longer, I repeated the experiment but then did it other way round (Inhaling warm air first then the cold one).

The result was quite surprising, for me anyway,that when my nose temperature was lower, the aroma was much more defined and vivid than the aroma I could discern when my nose was warmer. I felt that, when I was inhaling at warmer condition, aroma felt muddy and as if something have diluted the aroma.

This started to make me think how roasters roast beans in their roastry, if they have a set temperature when they roast or cup the coffee, as one might roast the coffee and cup them in a quite humid, warm environment, they might not pick up the aroma they sought after.

Furthermore, how this affects baristas who lives in hot and humid countries, how their nose is adapted to smell in those conditions, and if they will notice the difference when smelling between summer and winter- if their country have high temp fluctuation at summer and winter.

Feedback would be nice to see if my nose was completely wrong and I should go and check in the hospital, or if any of you guys experienced same things as me!

My educated guess will be that, humdity or warmer air contains less oxygen but more particles( like dust) which blocks the receptors in the nose, which distrups our smell.

Who nose :) ?

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Looking after customers and ourselves.

We, as a barista take care of our customers. From start to finish, we try to look after our customers, we try to deliver our promise to make them nice coffee.

We go into much details such as cleaning the basket, dosing, thinking about extraction yield, weighing our shots and so on.. we look after customers behind the machine without them realising, but are we looking after ourselves?

This week, I’ve been working around people who were quite ill, coughing and sneezing. I get very annoyed the fact they still come into work with the state they are in, they say they ‘have to work for the money’. In my opinion, that is being selfish, they don’t realise they might infect other people, and most importantly; they don’t realise customers are watching.

Customers do not look how our shot comes out, but they do look around our surroundings, such as hygiene and cleanliness.

Here is a example:

1. Customer pays for the coffee

2. Barista sneezes into his/her hands

3.Barista manual doses the grounds

4.Barista touches the portafilter handle and starts extraction

5.Few minutes later another barista pulls shots with same portafilter.

From that example above, i would say at least 2 people may have got infected.

Manual dosing when you have just sneezed onto your hands is just wrong. Some people might say the heat from the water will kill the bacteria, it might be true, but that is not important when the customer saw you sneezing, saw you not washing your hands and started to make their coffee. Would they come back?

In addition, when your hands are full of bacteria and you touch the portafilter handle, from that moment every single person who touches that handle will have same bacteria on their hands.

We want to deliver excellent service but sometimes we forget about the most simplest, yet most important things. If you must come into work when you’re ill, at least wear a mask, otherwise have a day or two off, don’t abuse your body.

Her are few things where we can do to prevent bacterias spreading, and most importantly things we can do to respect our customers.

-Buy quick dry antibacterial hand gel, so you don’t have to go back and forth washing and drying your hands.

-Sanitise portafilter handle (with anti bacterial wipe/spray) before other baristas start to use the machine.

-Eat lots of fruits, try to avoid caffeine consumption(or too much)

-Always remember that customers are watching you; even though you think they are not, you are on show, spotlight is always on you.

I know this might be a obvious post for some of you reading, but i see so many people forgetting about these simple things in cafes and restaurants, i had to point it out.

Making good coffee≠best customer service in the world, look back at what you do, start to think more about hygiene if you are alread not.

It’s always good to make nice coffees to our customers, but we should also look after ourselves and customers differently, not coffee wise.

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The past 6 month of my Barista life


I was ordinary. I was just another countless kid from far east Asia, from Korea to be exact, dreaming of success on foreign soil. A victim you could say, of a culture where it demanded you to study study study and have a nose bleed, become a doctor, lawyer or an engineer and make your parents happy; so they can talk about you to their freinds how successful i am.

For the past 12 Years i pursued something where, i couldn’t confidently say ‘I can do this all my life’. Until i came across coffee. Strictly it’s my 6th month of becoming a serious Barista, 6th month from where, i decided coffee will become part of my life and i will dedicate my time to coffee all my life. 

It has been a roller coaster ride (for me anyway) for the past 6 month, i have seen and experienced many things and most importantly met great people along the way and learnt incredible amounts of knowledge from these people.

I decided to write this post to take a step back; and see how far i came since 6 month ago, and how little i came until the point where i want to be. I just wanted to highlight the moments and people i have met, which changed the course of my Barista life and thank them for moulding me into what i am right now.

London School of Coffee, The espresso room and  Ben Townsend

At late March this year, i decided to take the VRQ Barista skill course in LSC. At that time i had no experience of using a tamper, did not know where coffee originated from and i thought you can extract coffee upto 35 sec. With my little skill on latte art, thats where i met Ben Townsend, i didn’t know anything about Ben, his backgrounds, his shop, practically everything. Ben amazed me every single day of that short 3 days course, i was dazed to be hit with so much interesting, yet challenging information about coffee, Ben changed me within 3 days of that course, i still remember when i had to serve Ben series of drinks and how nervous i was.

Luckily i passed both practical and theory exams and gained a merit, and i really wanted to learn more and more about coffee and asked Ben for a job, i still remember how desperate i was. I thought obviously, Ben will say no, he had the right to as i was so inexperienced, but Ben told me to come to his shop 2weeks later, and started my work at The espresso room.

I learnt so much when i worked with Ben at the shop, all my foundation was built up from which Ben has taught me, such as ‘Time to lean,time to clean’,  Ben isn’t a ordinary employer, he is a teacher and a freind, he made me settle quickly in a foreign environment, made my mind open up more and every moment was a joy.

If it wasn’t for Ben, i wouldn’t  be here writing this right now, it has been some time last time i worked for Ben, i always seem to miss him when i have the chance to see him, i miss The espresso room and i should make a visit real soon and work there once in a while. I have said this to Ben before but i will say it again, I love you Ben, you are a great inspiration!

Taylor St Baristas, Andrew, Nick and Laura Tolley

I remember meeting this bloke with a bike helmet and a jacket in The espresso room. Ben told me to make a shot of espresso for this guy and Ben introduced me to him, telling me he is one the Tolley’s who owns Taylor st Baristas, it was Nick.

I thought that would be it,  but 1 month later i got a call from Ben in the afternoon telling me to call Laura of Taylor st and meet her for a interview, i did that and few hours later i was at the Bank site, it was a struggle to find but i made it. I thought it would be an intense 30 min interview talking about coffee and myself, i remember taking a printed material about coffee and reading it until just i got into the shop and trying to memorise them. But it wasn’t a interview i thought of, there wasn’t any geeky questions about machines and origin of coffee, me and Laura just sat down and had a flat white, i remember telling Laura ‘ I just want to learn more and become better’.

After a nice relaxing chat, i was introduced to the staff, it was a complete different enviornment to The espresso room, the shop was big and very very busy, it was a new challenge for me, i realised 2 things. First it is going to be physically demanding to keep up with masses of order, second i had to maintain the quality of the coffee in a busy environment. With new challenge set, i thought i would do well honestly, but things were much different. I couldn’t keep up with the orders and i was so exhausted, in addition, i was also slightly intimidated as i was the only person with black hair, brown eyes and absence of OZ accent,and another great shock was that my knowledge on coffee was still paper thin, it fustrated me and motivated me to research more about coffee, study it and share things i learn with other people.

I didn’t meet Andrew until much later on after i started to work at Taylor st, i remember asking him if one of his brother taught at London school of Coffee, when it was actually Andrew who did. every time i worked with Andrew, he taught me great deals on coffee and skills. I found that Andrew and Ben had a similarity, they were both perfectionists. I learnt alot from Andrew just by watching him work, he is a great mentor, Andrew constantly feeds me with knowledge and news about coffee, he challenges the Baristas and his geekiness is praised among the staff, so much so that it is my mission to talk about coffee the most geekiest way with Andrew for atleast 30 minutes.

Without the help of Laura, Nick and Andrew, i would have given up after few days of work, i wouldn’t have fit in to Taylor St if the staff wasn’t welcoming and caring.

I feel really lucky to have met great people like Ben, Laura, Nick and Andrew in short space of time, and working for them is always a pleasure. This 6 month went past in a flash, i’m looking forward to the road ahead of me, the challenges i will face and people i will meet and learn from.

I thank everyone who has made me into a Barista i am right now. 

It is a long post…and boring one also.. i promise next time, i will write a post where you guys can read at least half of it before you fall alseep.

p.s sorry if i have mis spelt any word with crap punctuation, i should go back to studying english.