Skip to main content
thecoffeeprofessor
0
  • Products
  • Blog
  • About Us
  • Contact Us
thecoffeeprofessor
0
Cart0
  • Products
  • Blog
  • About Us
  • Contact Us
  • Home
  • The Coffee Professor Blog
  • Equation to a Perfect Extraction

Equation to a Perfect Extraction

Back when I used to train baristas (about 15 years ago) it was difficult to avoid overwhelming newcomers with the complexities of espresso extraction.

We definitely spent more lime training them on the intricacies of extraction than we did on how to texture milk. Most new baristas seemed to be more interested, however, in improving their milk texturing skills than in coming to grips with the seemingly endless variables of espresso extraction.

They seemed to naively think that espresso extraction was relatively simple, while latte art was more of a challenge. Latte art does seem to be a great motivator in engaging people with an espresso-based menu. However, in recent years, latte art has become more commonplace, helping to bring the complexity of extraction back into focus.

For cafes to compete in today’s market, it’s not enough just to pour a rosetta any more. Baristas have to know all about their coffee and how to get the best out of it.

Roasters have tried to help baristas by listing the details of coffee varietals, farm locations and roast styles on packaging. A recent development, however, are roasters listing the recommended espresso brew “recipes” or ratios. The ratios are written in a way that assumes baristas are familiar with and using gram scales for grinding and weighing liquid shots and TDS (total dissolved solids) meters.

While on the surface, this may seem like a logical approach to assisting baristas in achieving ideal extraction, I would argue that it opens up a Pandora’s box of issues.

The TDS refractometer has been marketed globally to baristas with a great cloud of seemingly creditable scientific fanfare. I believe, however, that the end result is not that reliable. In my experience, I’ve found that the refractometer can be highly inaccurate and that the methodology is so inconsistent that the information for the most part is pretty useless.

So, it’s unfortunate for me to witness coffee roasters using the refractometer to almost bully baristas into directing them on how to use their coffee beans. Well-intentioned baristas are set a task endlessly chasing an unattainable goal.

Refractometers work on the basis of measuring how much soluble substances bend the ligh t as it passes through a liquid. Given that different substances bend light at different rates, it is essential to know what substances are already in the liquid apart from coffee.

Damien Armstrong, from water filtration company Pure Coffee Australia, has explained to me that TDS in Sydney water can vary as much as 70 – 160 parts per million (ppm) and Melbourne water can be 30 – 110 ppm. But the refractometer only measures the total TDS, not the type. In taste tests we have conducted with minerals commonly found in water, each individual mineral differently affects the taste of coffee.

On top of this, a refractometer has to be temperature-stablised by allowing 30 – 60 minutes of ambient temperature prior to use. Otherwise, it will give you an incorrect reading. The temperature of water will also affect the rate at which light is bent as it passes through water.

To further complicate matters, certain coffee compounds in the TDS can only be read on a meter at specific temperatures. So, as the coffee starts to cool, they will disappear on your reading. A coffee has to be read at exactly the same temperature every time to get a consistent reading. To do a really accurate reading a barista should deduct the TDS that is contained in tl1e water to start with, to get a true coffee-only extraction reading. To date, I have yet to see any coffee professional do this properly.

To top it off, there are different micron filters that are used to remove colloidal material in the brew that affect the refractometer reading. Each different size filter will give you a different result. There is no standard recommended filter size for the coffee industry refractometer. So, many coffee professionals are doing the quivalent of passionately comparing Valencia oranges to Pink Lady apples and expecting them to be the same.

All in all, this can start to really do your head in. And yet, it is this analysis that is driving all the new brew ratios.

It is pretty anlazing how espresso extraction has come full circle in terms of a more scientific approach versus an artisan approach. Fifteen years ago we were selling grinders with gram scales and timers. Then, we found we got a more consistent result by using a more artisan approach, focusing on volumes rather than weights and visual flow rates rather than extraction yield percentages. Now we are back at it with our scales, timing and measuring. But I’m not sure if espresso coffee is tasting much better. I do know that when l came across the TDS evaluation kit with its recommended brew ratios in Milan four or five years ago, the closer we got to their recommended “ideal” extraction ratio window, the worse the coffee tasted. Now it may have just been the local water that caused the problem, but it made me very wary of the supposed benefits of this “renaissance” of the scientific approach lo brewing coffee.

One good barista in a highly sought after city told me that he altered the brew recipe-ratio from the one that the coffee roaster had insisted that they use. When the coffee roaster came by and unknowingly tasted his altered brew, the roaster proclaimed how good it was, completely oblivious to the fact that he had just tasted a completely different brew recipe.

When it comes to espresso brew ratios it is interesting to note now that shots are being weighed, that we have moved from traditional visual ristretto shots of 15 – 25 millilitres, espresso shots of 30 millilitres and lungo shots of 40 millilitres and using 7 – 10 grams of ground coffee (and all including crema), to shots that can be made from a double 22 grams of ground coffee and 50 grams of weighed liquid espresso. This would equate to low traditional lungo shots including crema, given that the volume of cream will be greater due to the volatility of the younger “new-wave” beans.

The trouble with lungo shots is that these shots tend to that more astringent than either espresso or ristretto shots. This is because coffee beans are predominantly made of cellulose (wood fibre) and the dynamics of filter baskets don’t efficiently deal with this matedal.

In defence of the old-school double­ ristretto, or “rizzy”, I did become confused with what can only be called a “super rislretto”, where a barista uses a naked porlafilter and brews wilh approximately 22 grams of coffee to produce as little as 10 – 15 millilitres of liquid. This is an extreme ratio and tastes way loo intense for most people. A modern approximate ratio of 30 millilitres of liquid from 20 grams of coffee is the rough equivalent of an old-school double rizzy and is still a nice tasting shot. Among all this confusion, there are a few simple tools lo ensuring a proper extraction. One is water treatment. I recommend  Reverse Osmosis water that has the precise natural minerals added back in every time we brew.  Just make sure they are the right minerals (tip: magnesium makes coffee taste bad). Also a clean machine makes a big difference. And this is one thing that science has thankfully improved greatly in recent years.

  • Facebook
  • Twitter
  • Pinterest
  • Google+

Leave a Comment?

Comments have to be approved before showing up

Service

Service

  • My Account
  • Track Order
  • Resolution Centre

About Us

About Us

  • About Us
  • Our Blog
  • Contact Us

Information

Information

  • Terms of Use
  • Privacy Policy
  • Returns Policy
  • Security Policy

Stay In Touch

E-commerce by Donohue Consultancy

  • Bank Deposit
  • PayPal Express

Terms & Conditions

Welcome to our website. If you continue to browse and use this website, you are agreeing to comply with and be bound by the following terms and conditions of use, which together with our privacy policy govern thecoffeeprofessor’s relationship with you in relation to this website. If you disagree with any part of these terms and conditions, please do not use our website.

The term ‘thecoffeeprofessor’ or ‘us’ or ‘we’ refers to the owner of the website whose registered office is PO Box A73, CARINGBAH, NSW, 1495, AU. Our ABN is . The term ‘you’ refers to the user or viewer of our website.

The use of this website is subject to the following terms of use:

  • The content of the pages of this website is for your general information and use only. It is subject to change without notice.
  • Neither we nor any third parties provide any warranty or guarantee as to the accuracy, timeliness, performance, completeness or suitability of the information and materials found or offered on this website for any particular purpose. You acknowledge that such information and materials may contain inaccuracies or errors and we expressly exclude liability for any such inaccuracies or errors to the fullest extent permitted by law.
  • Your use of any information or materials on this website is entirely at your own risk, for which we shall not be liable. It shall be your own responsibility to ensure that any products, services or information available through this website meet your specific requirements.
  • This website contains material which is owned by or licensed to us. This material includes, but is not limited to, the design, layout, look, appearance and graphics. Reproduction is prohibited other than in accordance with the copyright notice, which forms part of these terms and conditions.
  • All trademarks reproduced in this website, which are not the property of, or licensed to the operator, are acknowledged on the website.
  • Unauthorised use of this website may give rise to a claim for damages and/or be a criminal offence.
  • From time to time, this website may also include links to other websites. These links are provided for your convenience to provide further information. They do not signify that we endorse the website(s). We have no responsibility for the content of the linked website(s).
  • Your use of this website and any dispute arising out of such use of the website is subject to the laws of Australia.

Privacy Policy

This privacy policy sets out how The Coffee Professor uses and protects any information that you give The Coffee Professor when you use this website.

The Coffee Professor is committed to ensuring that your privacy is protected. Should we ask you to provide certain information by which you can be identified when using this website, then you can be assured that it will only be used in accordance with this privacy statement.

The Coffee Professor may change this policy from time to time by updating this page. You should check this page from time to time to ensure that you are happy with any changes.

What we collect

We may collect the following information:

  • name and job title
  • contact information including email address
  • demographic information such as postcode, preferences and interests
  • other information relevant to customer surveys and/or offers

What we do with the information we gather

We require this information to understand your needs and provide you with a better service, and in particular for the following reasons:

  • Internal record keeping.
  • We may use the information to improve our products and services.
  • We may periodically send promotional emails about new products, special offers or other information which we think you may find interesting using the email address which you have provided.
  • From time to time, we may also use your information to contact you for market research purposes. We may contact you by email, phone, fax or mail. We may use the information to customise the website according to your interests.

Security

We are committed to ensuring that your information is secure. In order to prevent unauthorised access or disclosure, we have put in place suitable physical, electronic and managerial procedures to safeguard and secure the information we collect online.

How we use cookies

A cookie is a small file which asks permission to be placed on your computer's hard drive. Once you agree, the file is added and the cookie helps analyse web traffic or lets you know when you visit a particular site. Cookies allow web applications to respond to you as an individual. The web application can tailor its operations to your needs, likes and dislikes by gathering and remembering information about your preferences.

We use traffic log cookies to identify which pages are being used. This helps us analyse data about webpage traffic and improve our website in order to tailor it to customer needs. We only use this information for statistical analysis purposes and then the data is removed from the system.
Overall, cookies help us provide you with a better website by enabling us to monitor which pages you find useful and which you do not. A cookie in no way gives us access to your computer or any information about you, other than the data you choose to share with us.
You can choose to accept or decline cookies. Most web browsers automatically accept cookies, but you can usually modify your browser setting to decline cookies if you prefer. This may prevent you from taking full advantage of the website.

Links to other websites

Our website may contain links to other websites of interest. However, once you have used these links to leave our site, you should note that we do not have any control over that other website. Therefore, we cannot be responsible for the protection and privacy of any information which you provide whilst visiting such sites and such sites are not governed by this privacy statement. You should exercise caution and look at the privacy statement applicable to the website in question.

Controlling your personal information

You may choose to restrict the collection or use of your personal information in the following ways:

  • whenever you are asked to fill in a form on the website, look for the box that you can click to indicate that you do not want the information to be used by anybody for direct marketing purposes
  • if you have previously agreed to us using your personal information for direct marketing purposes, you may change your mind at any time by writing to or emailing us: sales@gpawholefoods.com.au

We will not sell, distribute or lease your personal information to third parties unless we have your permission or are required by law to do so. We may use your personal information to send you promotional information about third parties which we think you may find interesting if you tell us that you wish this to happen.
If you believe that any information we are holding on you is incorrect or incomplete, please write to or email us as soon as possible at the above address. We will promptly correct any information found to be incorrect.