Speed vs Consistency

Posted by Matthew Patrick McLauchlan on

Speed Consistency_1

How do we measure speed? By using that old ‘distance divided by time’ formula from high school science, right? Sure, kilometers per hour or meters per second are the usual measures of rapidity, but in the coffee industry we’re more interested in cups per day as our unit of measurement; how many cups a café produces on a busy day can be a badge of honour or something to drop proudly into the conversation around the communal cupping table.

But as every busy barista will tell you, when the orders come streaming in and the printer starts to spit out dockets like an aggravated llama, the consistency and quality of the coffee being served tends to take a hit. So it seems as if there’s a constant battle between wanting to be as busy as possible and brewing the best quality, most consistent coffee possible.

But is service speed really at odds with consistency? Can you continue to serve at top-speed whilst still having the same amount of control over all the variables which make great coffee such a challenge to produce?

We at Common Man Coffee Roasters (CMCR) believe you can! But before we tackle the how, let’s talk briefly about what variables we need to be able to control and who looks after them. As the takeaway coffee queue begins to snake out the door, have a quick think about these issues -:

  • Brew water temperature/pressure. These parameters should be controlled (or at least maintained) by your espresso machine. The stability of these variables is one of the key indicators of quality in a machine.
  • Grind size. Your grinder should have this locked down for you, so make sure you’ve got it calibrated to your preferences well before the rush starts!
  • Coffee dose amount. Whether you’re using an electronic or a manually dosing grinder, your baristas need to be on top of this variable as it’s the start of the brew ratio.
  • Tamping technique. This needs to be consistent; always level and always firm.
  • Coffee distribution. You’re aiming for an even brew bed to form an even resistance as the brewing water passes through the puck.
  • Espresso extraction amount. Follow a recipe either by relying on a volumetric program or by using a scale and a keen eye. Your espresso extraction amount should be a consistent number and reflect your target brew ratio.

Reading this list of variables, it’s clear that to achieve great results at high speed, great emphasis must be placed on the quality of the equipment you invest in (including your scales). This equipment will be the foundation for eliminating variables, thus ensuring you produce high quality coffee with consistency. Once we take away our concerns over temperature, pressure, grind size and extraction amount, what’s left is our ability to hone both the process and our barista technique to a lethally efficient edge.

At the CMCR café, we get pretty busy. We’ve worked hard over the past few years to develop our processes to cope with producing upwards of 500-700 cups a day, whilst also producing the best quality brews we can.

Speed Consistency_2

This is our setup;

  • Get a fast, but accurate, electronic dosing grinder. We recommend the Mazzer Kony E or Mazzer Robur E. They’ve got great speed and consistency and even at top speed, they rarely vary by more than .5 of a gram once you’ve set the timed dose properly.
  • Buy a vessel for the coffee grounds to dose in to from the grinder. We’ve found these great little Tupperware-type things at Daiso which are all an identical weight (so there’s no need to tare them off constantly). They also fit the diameter of our VST Baskets perfectly!
  • Get a really fast reading scale that reads down to .1 of a gram. We use the BonaVita Digital Scale which has a super-fast reaction time and settles even more quickly; this is crucial for speedy service.
  • Use a comfortable, ergonomic tamper. We’re using a Pullman Wood tamper which fits in the palm of your hand very comfortably – this is something that can really drain the energy out of your arm if it’s not right. This tamper also has a beautiful flat tamping surface to ensure an even brew bed.
  • Invest in an espresso machine which gives you control and consistently replicates that control for coffee after coffee. Of course, we swear by our [Synesso]<link> Hydra. These machines provide us with so much control over temperature, pressure profiles and volumetric programming that we’re able to dial in a recipe to suit each individual coffee’s characteristics and replicate that over the span of a busy day with the reliability of a Swiss watch.

There’s a bit to take away from this article and it’s not just the fact that investing in equipment is a necessary part of a café’s journey to coffee glory. I hope we’ve also shown that there are some small adjustments which can make a significant difference to both your operational speed and your ability to produce high quality coffees consistently.

As always, if you need any assistance or recommendations on how to step your speed game up, get hold of a friendly CMCR team member. We’d love to help!

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New Lunar landing from Acaia

Posted by Matthew Patrick McLauchlan on

Lunar_1

With the rise of brew ratios as a cornerstone of specialty coffee preparation, so too have the tools in the barista’s arsenal evolved — and the new Acaia Lunar packs a hefty double wallop of style and substance to help hone the barista craft.

Nestled close to the grinder in specialty cafes, you’ll now often find a set of scales, ready and waiting to gauge the heft of the raw ingredients being dosed. Meanwhile, over on the espresso machine drip tray, the digits of a sister scale are rapidly ticking over, reading the outgoing beverage weight. Taken together, these two scales measure the ‘ins and outs’ of the barista’s recipe for deliciousness. Over the past few years, it has become evident that the scales available just weren’t built to accommodate the demanding coffee environment — there’s a sad graveyard out there somewhere, piled with units with damaged load cells and water-corroded battery housings.

And then there was the Acaia Pearl: an aesthetically beautiful and highly functional scale, the Pearl has become the weigh device of choice for discerning baristas over the past couple of years. Building on the success of this solid product, Acaia have zoned in on the wet, wild and fast drip tray landscape of espresso extraction and have launched their newest product: the Acaia Lunar.

Sized for easy fit onto the drip tray, this new scale highlights the expertise Acaia has at building high quality balances. An elegant aluminum body encapsulates a fully waterproof interior (!) ready to weather watery drip trays and errant extractions. On the usability side, the scales not only retain the handy USB rechargeable battery and Bluetooth app connectivity, but also add some really excellent new features. For example, multiple operation modes are available, including one super cool version which will auto-tare a cup put onto the scale and then proceed to auto-start the timer… cups on and you’re off!

Lunar_2

There’s loads of features:

2 Year Warranty: a longer warranty for a hardier scale. Covering the scale, USB cable and 100g scale weight.
Resolution: pinpoint your extraction weights with 0.1g readability. For reference purposes, you can also adjust to 0.01g resolution!
Weight Capacity: 2000g
Fast: 20ms response time provides an ultra-fast response time and instant readings.
Stability: featuring auto-zero tracking and creeping compensation technology to provide industrial grade stability.
Accurate: the highest internal resolution of up to one million counts allows for readability up to a tenth of a gram. This means that the Acaia Lunar even senses weight change due to evaporation.
Built in stopwatch: track the blooming, pouring and infusion time of your brew by syncing with the free app on your smart phone.
Brighter display: improved contrast for better visibility on the display.
Automated auto-off customisation: Decide when is most suitable for your scale to auto turn off, saving battery without accidentally turning off during brewing.
Rechargeable USB power supply: The battery lasts 20-30 hours.

Lunar_3

Here's what you’ll find in the box:

  • Acaia | lunar™ scale
  • Micro-USB cable
  • Acaia scale weight 100g
  • Acaia | aerial ™ heat resistant pad for lunar (black)

Sometimes a tool comes along and everything just clicks – it really feels that way when you start using the Acaia Lunar. Beautifully designed and thoughtfully built, it’s a great piece of kit that is aiming to last the test of time for high quality coffee prep. If you’re in need of a great set of scales for espresso (or brew) extraction, the Lunar will not disappoint!

This article was originally published on the Five Senses Coffee website: New Lunar Landing from Acaia.

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How to keep your Espresso Machine off my work bench

Posted by Matthew Patrick McLauchlan on

Machine cleaning_1While we spend a lot of time maintaining the smooth running of commercial espresso machines, our tech team also have a regular line up of home espresso machines coming through the workshop being given some TLC.

Domestic espresso machines come through the workshop for repairs all the time. They generally present with the same problems. Some are a result of general wear and tear, but some repairs are totally preventable. So we thought it was time to broadcast some of the common preventable problems to not only increase the longevity of your machine, but also to help your beloved friend produce liquid gold like it did the first week it arrived in your home.

We get all kinds of espresso machines through my door (Gaggia, Cimbali, ECM, etc) but we mostly deal with Expobar Minores and Isomacs so the following advice is mainly related to these machines. However it is still relevant to other machines. Each machine has their own intricate and unique problems, but all can start producing terrible coffee if you don't love and care for them. Now the title of my article may make it sound as if we just want to get out of doing some work (which is completely true), however nothing saddens me more than having to charge someone for fixing a problem that could have been avoided completely, or at least delayed, by following some simple steps.

I mean, you bought the machine in the first place because you wanted to make coffee at home just as well as they did in the cafe, right? Well, doing everything a good cafe does to make your $4 takeaway so exceptional is required at home too. This includes maintenance. Let's face it, you've spent all this money on a sweet machine and you don't want to have to fork out more cash for potentially unnecessary repairs.

Please note: this is not a maintenance manual. It's just a few tips, things that we noticed over the years from common issues we see with machines that come across our bench.

Big tip # won! Back flushing

Yeah, that's right, 'won', because that's the direction you're heading when you start doing this regularly. You'll be a winner! If your machine has a three way or solenoid valve (check your manual) then back flush, back flush, back flush, back flush, back flush, back flush, back flush, back flush, back flush, back flush, back flush, back flush, back flush!! Have I got that point across yet?

Most home machines make one or two coffees a day, then sit idle for 24hrs. If you don't back flush it's like eating a bowl of cereal, leaving the bowl on the bench and using it again the next day. Gross — and eventually you're going to run into problems.

Daily: After every coffee making session, you should back flush with water. Most machines come with some kind of cleaning disc or blind basket. Pop this into your normal handle and run the group until you build up some pressure and turn off to get that spurt out into the drain. Do this a few times. You should be able to see the water becoming clearer in that discharge.

Weekly: Run the same process, this time with some espresso clean (1/4 tsp) and before taking it out, let it sit for a few minutes. This will give the cleaning product a good chance to soak through the oils and allow you to rinse them away when you run the cleaning process again, this time without a cleaning product. If you turn out more than a couple of coffees, you’re certainly not going to do any damage by a more regular detergent clean.

Tip # 2 — Premium vs. regular.

Put good water into your machine. Filtered water. When using bottled water, make sure it doesn't say 'spring water' though, as that's not filtered water. Australia's water supply contains a large amount of ground water and, particularly if you're in Perth or Adelaide, heed this warning as tap water can be devastating to your machine. Combine heat, pressure and whatever makes up our regular tap water, and you've got a cocktail to make the strongest metal weak at the knees.

So if you want longevity from your machine, find the best quality, softest water possible. Good water will also make a dramatic improvement to your coffee quality. If using filtered water is a little pricy, a small water filtering jug like those made by Brita is a great start, but make sure you change the filter regularly.

Tip # 3 — Clean and open workspace

The cleaner you keep your workspace, the more your machine will love you. Roaches love warm electronic boards, and if they get in there, they can cause havoc. Quite simply, a dirty workspace will attract them, and the warm environment will make them call it home. So keep it all clean.

Tip # 4 — Don't panic and do some reading

You may think you don't know anything about that shiny thing on your bench, but hey, neither do many professional café baristas when they first get started. Coffee machines are pretty simple when you break it down. Take some time and learn a little about how your machine works. There are plenty of online forums out there; have a browse and see what you can learn! Of course, remember that you can also head along to the "Australian Barista Academy":http://www.baristaacademy.com.au/ to get some hands on experience.

Tip # 5 — Troubleshoot

When you understand your machine and something goes wrong, step back, put one hand under your arm and the other on your chin and have a think about what's going wrong. Here's a few trouble-shooting examples combined with some very common issues:

Machine cleaning_2

Example 1 — Your machine suddenly pours shots very slowly or not at all.

  1. Is there enough water in the reservoir and is the water or any hose inserted properly?
  2. Check your grinder setting. It may be the same as yesterday, but do you have different beans in there that require a coarser grind setting?
  3. How long since you last made a coffee? Many cheaper domestic machines come with a dual floor/wall/pressurised basket (Might be worth googling, but basically these baskets have many holes on the inside, but only one hole underneath for the coffee to escape. See above picture). This combined with the oils and consistency of espresso, multiplied by a lack of basket maintenance, equals: blocky blocky.
  4. Take the handle out to see how the water flows without the handle in. If it seems restricted, the shower screen could be blocked. (If you have an espresso machine, you should also invest in a stubby screwdriver, so you can easily remove the shower screen and clean it regularly).

Machine cleaning_3

Example 2 — None or only a small amount of steam

  1. Isomac/Expobar — Check the steam gauge. If it's anywhere from 1 to 1.7 bars and stable (depending on where it's set) that means the machine is doing its job and you can start looking at other possible causes.
  2. All machines — Check the steam tip. Yes, I have actually had a few machines come to me after going through an entire warranty process, and it has taken me all of 15 seconds to stick something pointy in the tip and have the machine working again (see picture above).
  3. Always remember to purge the steam wand before and directly after use to remove any milk which may be in the wand.

I hope you find these tips an inspiration to not only go on a sudden cleaning rampage, but also to implement a five minute weekly cleaning routine. Investing just five minutes a week will help to improve both the longevity of your espresso machine and the quality of your coffee. Your tongue and wallet will both be grateful.

This article was originally published on the Five Senses Coffee website: How to Keep your Espresso Machine off my Work Bench.

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Coffee with Milk: I'd like mine Coffee Flavoured Please

Posted by Matthew Patrick McLauchlan on

Milk

These days, most baristas are accustomed to thinking about and controlling the many factors that affect an espresso’s taste. They may have also honed the art of perfectly steaming milk and be pouring beautiful designs on their drinks. Today we’ll be talking about something which is often overlooked: the amount of milk we’re mixing in to that coffee, and how it affects the strength and flavour of the coffee we drink.

The ratio of milk to coffee is such a simple thing to control, it’s amazing that so many people don’t even consider changing it. At home, a barista will often just use whatever mugs they have in the cupboard, while in a café, an owner will often simply buy the cups they like the look of, or whatever is easily available to them. However, the size of the cup will be a key factor in determining the strength and drinking experience of the final coffee. In fact, there’s an argument to be made that it’s the only decision we make that will change the final strength of the coffee. That argument goes like this: for a given espresso machine and basket, there are a small range of viable doses we can use. Although it is possible to change our basket size, this is not common practice. Therefore, with our dose fixed, we will need to make a decision about the brew ratio. Although this decision will affect the strength, it makes much more sense to base the decision on getting the tastiest brew we can. Therefore, we end up with an espresso of fixed strength and size, and the strength of the final beverage will be determined by the milk we mix into it.

So, what size cup should we be using? Firstly, I think we need to set some goals for what we want out of our milk drink. Personally, I want mine to taste primarily “like coffee” and not primarily “like milk.” This will mean different things to different people, but by tasting some different ratios you should be able to find where your goalposts are. The character of the milk we’re using is certainly going to weigh in here: a creamier milk or a milk with a stronger inherent flavour will be more present in the profile — sometimes deliciously and sometimes overwhelming the coffee element. Then we have the amount of foam. As many a barista competitor will know, a foamier cappuccino will taste stronger, as we end up with less milk and more air in the cup. The brew ratio of the espresso is also going to affect things: let’s compare a single espresso with a 22g yield to a longer, 33g shot. The second shot will often have a higher extraction, leading to an increase in strength, but it will also displace a whole 10ml of milk, adding to the perceived strength of the drink. Lastly, we should consider the roast profile of the coffee used. Generally speaking, a darker roast will lead to increased strength perception in the cup. However, at a certain point a darker roast will start to introduce roast defects into the cup, leading to a coffee that may taste a bit stronger, but not in a good way (ashy, burnt, bitter.) At Five Senses, we roast to maximize the development of the particular coffee, without introducing any roast defects. The relationship of cup size to perceived value for money is also not to be discounted, but will have to be up to café owner’s judgment of their target market to determine. However, it’s my experience that for every “bigger = better” customer out there, there is another “smaller = quality” customer just around the corner.

Now, let’s talk numbers. Fair warning: we’re veering into personal opinion territory here. My first piece of advice is: measure the actual volume of your cup, as many cups are as much as 10-15% off their advertised volumes. Now, we’ll need an example espresso: let’s use a single shot of our 22 Martin blend, pulled to our standard recipe. This results in two single shots, 22g in size, pulled at a 1:2 ratio. To me, this coffee tastes delicious in cups in the 150ml-190ml range. At the 150ml range the coffee is punchy and certainly the dominant flavour, while at the 190ml end the coffee is creamier and sweeter, but still definitely in balance with the milk flavour. Going too far outside this range either washes out the coffee with excess milk flavour, or results in a drier, “punch in the mouth” type intensity of flavour.

The 8oz Problem Café owners at the moment are presented with a unique problem when considering the size of takeaway cups to use. The arbitrary standard cup sizes available historically have been 8oz (235ml), 12oz (355ml), and 16oz (475ml). These sizes are normally referred to as small1, medium and large. In recent years, many specialty cafes have stopped selling the 16oz cup, leaving them with a line-up of 8oz and 12oz. This presents an obvious problem: there’s no way to get the same strength/flavour profile in both cups with our standard single or double shot. Which means we either sell a single shot 8oz that’s weaker than we’d like, giving our customers a sub-optimal experience, or put a double shot in both the 8 and the 12, giving our small customers an extra strong coffee. The additional downside of this approach is that our material and staff costs are very similar between the two drinks, with only a small amount of milk between them. This is an unfortunate situation, but it has an obvious solution: substitute the 8oz cup for the smaller, 6oz (175ml) version. This puts us right in the previously identified sweet zone for our single shot, and lets us achieve a consistent flavour strength across both sizes and a dine in and take away flavour profile. In my experience, changing the strength of your coffee is a really good way to put your customers off, so this consistency across your offerings can be key.

In conclusion, there are many potential benefits to be had from considering the amount of milk you put in your flat white, and the size of cup you’re serving it in. It is an essential factor in the enjoyment of your drinks, and I hope this article spurs you to investigate further. Although I firmly encourage you to make your own mind up about this, I wanted to leave you with some concrete recommendations:

  • Using a shot of approximately 20g size, a cup size of 150ml-200ml will give you an excellent balance of strength and flavour.
  • This translates to using 6oz and 12oz cups for takeaway, with a single shot in the first and a double shot in the second.
  • If you are set on using an 8oz cup, it would make more sense to keep the double/single ratio and pair it with a 16oz cup. By using a larger dose in a bigger basket we can avoid the coffee flavour being lost in the extra milk.

Happy drinking!

1. This means the "small” is far larger than most normal dine-in cups, which is compounded by some “8oz” cups I’ve encountered in the wild hitting actual volumes of up to 280ml.

This article was originally published on the Five Senses Coffee website: Coffee with milk: I’d like mine coffee flavoured please.

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Contact for Content - Exploring Time During Espresso Extraction

Posted by Matthew Patrick McLauchlan on

In this blog post I’ll be exploring the time component of an espresso recipe and exposing why it should be the most flexible part of your recipe when it comes to troubleshooting.

When we measure the duration of our extractions, what does this measurement actually indicate? This question frequently comes up, in one form or another, during our classes at the Academies. Extraction time is a rough indicator of the total amount of content being removed from espresso, but it doesn’t exist in a void and it’s important to understand the other factors interacting with this variable.

This becomes apparent while working with the same roast batch of coffee from one week to the next. Here’s an example of what typically happens if you use a static time target for your recipe:

Example


1-7 days 7-14 days 14-21 days
28 seconds 28 seconds 28 seconds
Lower extraction yield Average extraction yield Higher extraction yield
17.8% EY 18.5% EY 19.2% EY


A 28 second extraction might taste under-extracted in days 1-7 after roasting, amazing from days 7-14 after roasting, and increasingly over-extracted from days 14-21 and onwards.

What gives?
The problem lies in that the influence of a static extraction time will be defined by the flow rate (how quickly the water is flowing during that time). Flow rate, in turn, is determined by several factors that may change and interact in different ways over the lifespan of roasted coffee:

  • Gas content (CO2)
  • Grind particle range
  • The pressure profile of the espresso machine
  • Dosage in the basket
  • Distribution of coffee in the basket

If we add those elements to the table above, it should provide a snapshot of why flow rate changes occur:


  1-7 days 7-14 days 14-21 days
Extraction time 28 seconds 28 seconds 28 seconds
CO2 Highest Medium Low
Moisture Highest Medium Low
Extraction result Under extraction Good extraction Over extraction
Grind Most coarse Optimal Finer
Pressure 9 bar 9 bar 9 bar
Extraction yield % Lowest Optimal Highest
Taste results Under extracted Optimal Over extracted


As outlined above, CO2 levels and absorbency of coffee particles help to create differing levels of resistance for our brew water travelling through. Only by aging your coffee can a more static time be used to achieve optimal results. However, for times when coffee isn’t optimally aged, it’s wise to adjust your extraction time accordingly.

Quality
Assuming a consistent brew temp and pressure for now, two of the most important brew parameters to maintain in order to achieve a repeatable extraction yield are brew ratio (dose vs beverage weight) and the size of your ground particles.

Changing the size of ground coffee particles is the principal way baristas will alter their flow rate in order to achieve a consistent extraction time. Unfortunately, if we lock time down as a static variable, our grind has to change quite significantly from a coarse grind while the coffee’s fresh to a much finer position as it ages and loses its natural resistance.

Here’s the testing we’ve done to show this effect.


9 Days old - coarser grind

Dose Beverage Time TDS Yield %
20.00 38.91 26.63 9.38 18.91

16 Days old - finer grind

Dose Beverage Time TDS Yield %
20.00 39.04 26.88 9.55 19.30


These are the average numbers resulting from a batch size of 8 samples per test. As you can see, the brew parameters here are super consistent (just over 0.1 gr for beverage weight, 0.2 of a second, and exactly 20gr dose), but the TDS % and extraction yield % are significantly higher across roast dates.

These results are from the same coffee, from the same roast date and batch, prepared over a two week period, with the time static for both recipes. So when keeping the recipe exactly the same but altering our grind, we receive different extraction yields and different cup results.

As we altered the grind setting to be finer in order to keep the time in a static position, we have allowed more content to be dissolved, resulting in a higher extraction yield (and a potentially tastier extraction too). By keeping the grind in the same range but allowing for a lower time target, we could achieve a more consistent extraction yield.

Use time to achieve consistency of quality
When managing the quality of espresso, it’s wise to use an espresso recipe in conjunction with tasting (hopefully there are no surprises there!). A refractometer is a very handy tool if you can get one. A recipe is a great starting point for any coffee but, as outlined above, you’ll need to adjust the recipe somewhat if your coffee isn’t optimally aged or providing the results you expect.

After adjusting your grind to achieve a recipe, taste and/or measure the extraction yield. If you believe your espresso tastes over-extracted, you’ll need to adjust the time target to a lower number and vice versa.

Quick Tip: When changing your grind coarser to achieve a lower time target or finer for a higher target, if you’re using a Mazzer Robur, an adjustment of 1 notch on the grind collar will alter the time by 3-4 seconds. To tweak your espresso extractions, move by ½ notch increments (2 seconds at a time) and taste as you go. (Note: these rules of thumb will depend on a number of factors including the wear on your burrs — pay attention to the time impacts of your adjustments and you’ll soon learn the ins and outs for your specific grinder.)

This creates a standardised approach to dialling in any coffee, no matter what origin, roast development, density etc. There’s a time in that range when you’ll be extracting optimally and we want to hunt that time down and stick to it.

Here’s how this looks in practice:


Starting point

Dose Beverage Time
20g 40g 28s
Coffee age Tastes Adjustment
27 days overall good.
Slightly underextracted/sour,
lacks body and sweetness.
1/2 notch finer

New recipe

Dose Beverage Time
20g 40g 30s
Coffee age Tastes Adjustment
27 days balanced, sweet, great Just don't


By the above example, 30 seconds appears to be a better extraction time for this coffee. Is this therefore the time which will always deliver that amazing spro? Not likely.

However, with the process and context we’ve discussed above, you should be able to tweak your recipe to hone in on the delicious zone for any coffee — remember, learn the rules and use your sense of taste to know when to break them!

This article was originally published on the Five Senses Coffee website: Contact for content – Exploring Time During Espresso Extraction.

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