portaspresso
The Finest Portable Espresso
The Ultimate Espresso ExperienceProductsSalesMaster ClassServiceContacts
Espresso Coffee Pressure Profiling
Application of Pressure Profiling
Master Class

Scroll down to read about advanced Portaspresso System techniques

  

 

 



Master Class

This page is devoted to more advanced techniques to help you go from great espresso to perfection ... well, as close as possible anyway! In addition to describing the features and operation of the Portaspresso Specialty Coffee System, the various types of grinders and espresso equipment will also be discussed. It is my intention to help as many people as possible to improve their coffee knowledge and espresso techniques, because the more you know, the more you will appreciate the Portaspresso System.

Firstly, I would like to state that all that follows is the result of my personal experimentation and interpretation, and I am open to all feedback and suggestions. Secondly, I would like to acknowledge that not everyone is at the same place in their coffee journey, and their destinations are not always the same. My destination is perfect espresso, and the information and techniques described on this page specifically focus on espresso coffee.

Fresh Roasted Coffee

The first step to perfection is quality fresh roasted coffee beans. Unless you are a skilled roaster, it is best to source your coffee beans from a specialty coffee roaster. Most roasters do a very good job, but it really comes down to personal preference. My advice is to experiment with as many different roasters and blends as possible, and revisit earlier roasters as your techniques improve and experience grows.

The way your coffee is transported and stored has a dramatic effect on espresso quality. It is essential to avoid moisture, heat and light as these will cause fresh roasted coffee to deteriorate rapidly. Minimise the time between purchasing your coffee and storing it in a cool, dark and dry place. Unless you live in a cool, dark and dry place, store your coffee for immediate use in a frost free refrigerator in its original bag. The bag should have a one-way valve to release CO2. If the bag is not resealable, carefully cut the corner, fold the corner tightly after use and seal as best you can with a clip. If you have more than one bag, store all that is not currently being used in a frost free freezer until required.

Unless you live in a cool, dark and dry place, do not store your coffee in the cupboard. Doing so will quickly transform your quality coffee into something resembling what you buy from your local supermarket.

Grinding Equipment

The next step to perfection is grinding your coffee to the correct size with a quality grinder. There are three basic grinder types: blade, flat disc and conical burr.

Blade grinders are cheap nasty things that smash your coffee into something that resembles espresso ground coffee. The basic problem with these is that they smash rather than cut, resulting in uneven particle size and a lot of fines (fine coffee dust). Even when you measure the coffee and use a timer, it is still difficult to get the grind right. Even when you do get it right, extraction is limited due to the quantity of larger particles, and you can taste the fines that escape through the filter. If you have a choice, it is best to avoid these grinders.

Flat disc grinders are significantly better than the blade type, but are significantly more expensive. For the most part, they do quite a good job, and most people would be happy with a quality grinder of this type. However, their cutting action is relatively fast, which generates heat and consequently affects the quality of the ground coffee. The cutting area is generally narrow, which causes the coffee to smash together more than desirable. This causes fines, but at a much lower level than blade grinders. Most people will not pick fault in a quality flat disc grinder, and if you are unable to buy a better type, my advice is to never try a quality conical burr grinder. Once you do, you will want one!

Conical burr grinders currently offer the best grinding action. The cutting action is relatively slower than flat disc grinders, which results in less heat. They also have a larger cutting area, and the cutting action is more shear than other grinder types. The resulting grind is generally consistent with minimal fines. If it is within your budget, a quality conical burr grinder is a great investment. You will taste the difference.

The Rosco Hand Grinder uses a conical cutter, has stepless adjustment, has a thrust ball bearing, and is constructed with fine tolerances. This means that the grind quality is as good as any conical grinder. It is very efficient, and as a hand grinder, it is very fast. It is capable of grinding 20 grams of coffee in 30 seconds, which is more than tolerable for personal use.

Whichever grinder you choose, you want to ensure that all old coffee grounds are removed before use. Coffee deteriorates within minutes of being ground, so removing old grounds is essential for quality. Unfortunately, it is very difficult to remove old grounds from most grinders. You can grind a small amount to flush out the old coffee before grinding into your filter head, but this is quite wasteful and does not do a thorough job. Also, if you have a choice, do not buy a grinder with a doser for home use. A doser just adds to the places where old coffee can accumulate. This is another advantage of the Rosco. The Rosco can be used for single shot loading, which is when the grinder is filled with just enough beans for a single shot. Other than brushing away excess coffee from beneath the cutter, there is nowhere for old coffee to accumulate. Single shot loading is also great for using different coffee blends or origins without the need to empty a hopper.

Espresso Equipment

Once you have a quality grinder to grind your carefully selected fresh roasted coffee, the next step to perfect espresso is the espresso machine.

There is no distinctive line separating domestic and commercial machines, but rather a gradual improvement in quality and design features. In general though, domestic machines do not have a boiler whereas commercial and semi-commercials do.

Even though domestic machines vary significantly in price, their fundamental extraction designs are not substantially different. The methods through which they control temperature do not function well enough for high quality espresso, and their pump performance is generally much lower than commercials. Nevertheless, you can make quite a good coffee with even a cheap domestic machine if you have a good grinder and know what you are doing. In fact, a skilled person can make a better coffee with a cheap manual machine than an expensive automatic because the operator has more control with a manual machine. Domestic machines certainly have their place, but if you are seeking perfection, you need to look further.

Those who want quality coffee at home generally end up with a semi-commercial machine. Having a boiler enables much higher control over temperature, and they normally have a good quality pump. The main difference between semi-commercials and full commercial machines is capacity. Full commercials have larger boilers and pumps to cope with higher use, and are fitted with multiple group heads. Higher end machines have more control over variables such as temperature, pressure and profiling, but their fundamentals are not much different to semi-commercials. The only thing to say about these machines is CLEAN THEM ! And even though the group heads often come with two outlet spouts, do not extract more than one shot at a time per group head. Regardless of its distribution, you can only pump so much water through coffee before it starts to taste like razer blades! A volume has not been specified because it depends on a number of variables, one being personal preference. The best thing is to experiment with different volumes to find out what works for you.



 


Pursuit of Perfection with the Portaspresso Specialty Coffee System

The following information is for users of the Portaspresso System to help unlock the system’s full potential. Consider this information as a starting point on your journey to espresso perfection. With practice and experimentation, there is no reason why you cannot make the most sensational coffee you have ever tasted.

Rosco Preparation

Measure out approximately 20 grams of coffee beans. This is about the same volume of a 50 ml shot glass or a slightly overfilled double shot filter basket. It is also a good idea to experiment with slightly more or less coffee to find out what works for you.

You now want to set the grind size on the Rosco. Due to the high quality grind, you can effectively use a large range of grind sizes for extraction through the Rossa. In general, the finer the grind, the higher the pressure, but with careful manipulation, you can obtain similar pressure and flow within a relatively broad range of grind settings. The difference is the taste, and this will vary between coffees and their overall conditions. For example, the same bag of coffee will respond differently from the first shot to the last, especially if a week or more has passed since it was opened. Again, the key is experimentation.

Remove the cap from the Rosco and fill with the measured beans then refit the cap. Set aside and prepare the Rossa.

Rossa Preparation

Remove the filter head and wipe the piston and seal area with a damp cloth. Of course it is already clean, but a quick wipe ensures any slight residue is removed. If necessary, put a few drops of dishwashing liquid into the vent holes on top of the press unit then fill with water. Shake around, then fully unwind the spindle, run a damp cloth along the thread, then rinse and put aside. Take the filter head and remove the basket. Clean as necessary to remove any residue, and refit the basket.

It is not necessary to use dishwashing liquid every time, but you do need to lubricate the internals each time with water and wipe the thread as described. Minimising friction and any resulting vibration or shaking is critical if you are trying to make great espresso even better. It is also unnecessary to remove the filter basket each time providing you clean it often enough. The accumulation of small things really does make a difference.

Grinding and Tamping with the Rosco

Take the filter head with basket fitted and preheat with warm water. Shake out any water and towel dry. It does not need to be perfectly dry, just enough to prevent water from entering the grinder. Fit the filter head into the Rosco then grind until all beans are through. Remove the filter head and you will notice that the turning action of the cutter combined with the narrow space has effectively pre-tamped the coffee. Complete the tamping and ensure that the puck is square.

Preheating the Rossa

The importance of preheating the press unit correctly cannot be overstated. Temperature control is arguably the most important aspect of extraction, and is the main reason why espresso from domestic machines is never perfect.

Ensure you have boiling water at hand. Invert the press unit and fill with boiling water to just above the basket seal. Hold for about 20 seconds then empty (usually into your cup to ensure it is also preheated) and refill. Hold for about another 5 seconds then empty and refill to about 1 cm below the top of the cylinder bore.

You can adjust the temperature for extraction by varying the 5 second period. A milk thermometer can be used to measure the temperature, but holding your finger on the semi-insulated brass area beneath the inverted device gives a surprisingly good indication of internal temperature.

One more thing to consider is whether or not you reboil the water during the waiting periods. You should generally do it the same way each time otherwise you will lose consistency. However, boiling just once is best when conditions are warm and when indoors, but maintaining water on the boil is best for consistency when in cold or windy conditions. Again, experimentation is the key.

Extraction with the Rossa

Timing and smoothness is the key to good extraction. If you work too slowly, you risk losing the optimum temperature. If you are too frantic, you risk shaking the device and disturbing the puck. You want to work quickly but smoothly.

Once the press unit is preheated and filled ready for extraction, immediately fit and tighten the filter head. Turn the device to the upright position and immediately start turning the crank handle. This is where the magic begins!

Basic Technique

Before experimenting with other variables, it is advisable to build proficiency with the basic technique as follows:

Turn the spindle in at a pace that enables you to hold the device steady. As pressure increases, slow your turning speed. Once the espresso stream emerges, watch the stream and control your turning speed at a pace that maintains a smooth and steady flow. Stop extraction once the desired volume is reached and immediately remove the device from above the cup.

You do not want residual drops in the shot because their extraction characteristics are different to the main flow, and can potentially affect taste. Also, don’t be concerned about pressure. The form and colour of the espresso flow gives a more accurate indication of what is going on, as does the taste.

Pre-infusion

Once you begin to develop a smooth and controlled technique, you can start to experiment with other variables. The first is pre-infusion time. In general, the oilier the coffee, the longer the pre-infusion. If your coffee is old or has been exposed to the elements, you need to get pressure onto the puck as quickly as possible, so minimal pre-infusion is the key. If you are stuck with dry coffee, filling the chamber to the top of the cylinder bore helps to minimise pre-infusion time. You will be surprised how good old coffee can taste. The taste is not as full, but it will be very smooth. Of course you don’t want to make a habit of using poor quality coffee, but it is inevitable that from time to time you will have no choice, especially when on vacation.

Quality coffee gives you significantly more options. Start by turning the spindle approximately half way down, until slight pressure is felt. Hold the device perfectly upright and pause for approximately 10 to 20 seconds then continue with normal extraction. Experiment with different pause times, even up to 30 or 40 seconds. You can also experiment with different pause pressures, such as turning the spindle in until moderate pressure is felt, then hold for the pre-infusion pause. The naked filter head lets you see precisely when and how the espresso emerges. Use a mirror placed at an angle to gain a clear view.

Pressure Build-up Profile

This is the relationship between speed and pressure build-up prior to the start of extraction. A good starting point is to begin with the slow technique. Turn the spindle from start to finish at the same speed as that used during the extraction phase. This is a slow and steady approach and works very well with exceptionally high quality coffee. Next try a high speed, but not so fast as to shake the device. Of course you need to slow as extraction begins. Also try a fast start with a gradual slowing as pressure increases. Another variation is a slow start then increase speed as pressure increases then slow as extraction begins. A variation of this last technique is to continue at speed until a full thick espresso stream is formed then slow to a controlled pace. Combining these pressure build-up techniques with the pre-infusion techniques is the key to unlocking a particular coffee’s full potential, and discovering the best combination is essential for espresso perfection.

The Extraction Phase

The main focus during the extraction phase is to maintain a smooth and steady espresso flow. The stream will wobble around a little when the Rossa is used freehand, but this is actually desirable because the slight movement of the stream tends to minimise disturbance in the cup. You will find that forming and maintaining a steady stream requires higher pressure at the beginning of extraction and a gradual decrease as the shot progresses. If you are aiming for perfection, subtle mid extraction pressure adjustments are often required due to unanticipated flow variations that occur inside the puck. These variations are felt through the crank arm and adjustments to this feedback become almost automatic as your technique improves. Experiment with variations for yourself, but be sure to take note of the stream form and colour as this is your main reference.

Summary

As a whole, the combination of available variables both before and during extraction makes the Rossa a truly unique device for anyone seeking the ultimate espresso experience. You can vary coffee grind size significantly more than with a conventional machine, and you can vary temperature, pre-infusion time, pressure build-up profile, pressure during extraction, and adjust for unanticipated variations during extraction. I hope this page has provided you with enough information and insight to start you on your journey to espresso perfection, and I also hope you experience the full potential of the Portaspresso Specialty Coffee System.

Click to read about Espresso Coffee Pressure Profiling