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Let your naked portafilter teach you
Some time ago I made the decision to supply all our machines with naked portafilters
These changes i never make lightly, so please understand that there is a strong driver behind it
I am writing this post just to make sure that you are letting your naked portafilter teach you about your espresso making technique
The point of offering naked portafilters is not so you can see the pretty patterns as the espresso flows from the portafilter; it really is to help you raise your performance
Until now it has been pretty chaotic getting this thing to fly - this is the first year where there is a bit more time to put the feet up and consider things, rather than being completely consumed with tactical responses to fast moving challenges
So an obvious benefit of a naked portafilter is it allows you to see what is going on, but we need to come back to that as you need to know what you are looking at in order to benefit from this
Second, the espresso is now falling directly from the bottom of the basket into your cup. This eliminates the possibility of taste degradation arising from a spouted portafilter that is not clean inside the pathway that the coffee travels along from the point it falls from the bottom of the basket until it drops from the bottom of the spout on the portafilter. That again is an easy to understand physical benefit
So, looping back to the key point, which is the ability to see the shot. Thats great, but now you need to know how to 'read' what you are seeing
Until now i have handed out 1 gram per second of espresso in the cup as a rule of thumb to get people underway
However, as some of you will have already discovered a simple rule like this does not protect you from differential flow rates at different places in the puck - it is merely an average and assumes that the difference in the rate of flow in different parts of the puck is not too great
But, what if that is not true? What if you have channelling? If you have heard of the term 'channelling' but have no idea what it might mean, there is a clue in the word itself - water that discovers an area of less resistance in a medium that it is flowing through will naturally channel or direct itself into that path of least resistance as the rate of flow is higher - this is basic physics at work
You see this effect at work in nature wherever water is being held back or dammed in some way: it all works well until the water manages to find a path of less resistance in the medium that is holding it back then the moment that the rate of flow increases in that path of less resistance the water scours out the media that is lying in that path of less resistance, which in turn allows even more water to flow down that path, which in turn scours out more and the rate of flow is all the time increasing. When it occurs in nature on a large scale the damaged to property and person is often catastrophic. When it occurs in your espresso puck the results are equally catastrophic, at least as far as your quest for exceptional espresso is concerned
The wonderment should not be directed at why your espresso does not always extract evenly, but rather that it ever extracts evenly at all. Be under no illusions, in deciding to make espresso you are picking a fight with physics. Once you understand that it is quite remarkable that forcing hot water through ground coffee results in an output that is drinkable
Another helpful point is not to view coffee grounds as scoria or rock or grains of sand that are to all intents non-permeable when water flows through them under pressure, but rather to think of coffee as a slightly coarse saw dust, for coffee is closest to wood in terms of its structure and how it performs when it comes into contact with water
So. What to do?
I think the easiest place to start with this topic is to consider what an 'perfect' extraction looks like, or in other words, an extraction where the rate at which the water flows through the puck is as uniform as possible at all points through the puck
It is important to understand that whilst the output from your grinder may appear uniform, it is not. The grains are all slightly different in shape and size
When we speak of distribution we are talking about arranging this mix of different sized and shaped coffee grinds as evenly as we can throughout the entire puck. That's right, its not easy, and the better the grinder the easier it will make this task for you, largely by delivering grounds of a more uniform size and shape
It is quite possible that you have never seen perfect yet, so you might have to imagine it for the moment, but i will try to deliver a video clip of a perfect start to a shot soon. in essence you can expect tiny tiny beads of espresso 'sweat' forming in the holes in the bottom of the basket during the pre-infusion phase which appear first near the outer perimeter of the basket then appear toward the centre. if you get coffee jetting out (spritzing if you are american) at this point, or even worse flowing out, the shot is a dud. release the lever gently and start again. assuming you don't get spritzers or coffee flowing during pre-infusion then at the end of your pre-infusion phase you can release the lever and as the pressure of the piston is exerted onto the water on top of the puck of coffee those beads of coffee sweat will quickly be on the move, being pushed out and then if the flow is roughly uniform across the entire surface of the puck they should be drawn toward the centre where they will form a single central cone and flow down into your cup
If you have made a reasonable start you will not get spritzers nor flow during pre-infusion but there is still a good chance that when you release the lever that you will be cursed with multiple streams flowing from the bottom of the basket. this is ok if you are just getting to grips with it, but for anyone who has had their machine for a while this is still a fail I'm afraid
The trick if you are at this what i call intermediate level of proficiency, and by the way i believe a lot of people are stuck at this level and have no idea how much hidden taste potential is locked inside their LONDINIUM I, you need to work on your distribution. Lets assume for the moment that you have a wonderful grinder and it is in no way to blame for this state of affairs, for it is completely within the realms of possibility to have what i call 'all the gear and no idea'
If your distribution is poor, particularly if you were experiencing spritzers or coffee flow during the pre-infusion phase it is very common to compensate for this by grinding finer. I am thinking in particular here of manual grinders, and to a lesser extent electronic or deserves grinders. Why? Because as annoyingly time consuming as they are to keep free of stale coffee the time honoured doser mechanism on a coffee grinder is actually hard to beat as far as nicely distributing the different sized and shaped grinds is concerned. Yes as fashionable as it is for speciality coffee types to mock the Italians because they don't take a refractometer to bed with them at night the Italians have some pretty trick engineering solutions across the board, not just in coffee technology, but the ubiquitous vaned doser mechanism is definitely one of their better ones - despite its shortcomings it does the job it was designed to do very well
conceptually i like to approach the challenge like this: for any given dose i like to grind as coarse as i can whilst still maintaining a uniform flow across the puck and hitting my target flow rate, so this could be 1g per second in the cup, or perhaps you might have a preference for a slightly slower (faster) flow rate; that is also fine - all you really need is a consistent methodology to resolve this issue as it is going to confront you every single time you make espresso. and at this point this is where i like to re-iterate the importance of sticking with one roast if your skills have you at this point on the espresso making curve. every time you change the roast you start solving this problem from scratch again. buy yourself a kilo (2 pounds stateside) of your favourite roast and just work it shot after shot, back to back, until the whole bag is gone. obviously you don't need to taste easy shot, or all of each shot, but if you taste part of the shots that you begin with and then part of the shots throughout the process, every fifth one that looks good perhaps, you will astound yourself with your rate of progress i absolutely promise you
as you eek ever so slightly coarser your poor distribution and or tamping will be guaranteed to result it spritzer, pre-infusion flows, and good old fashioned channelling once the spring pressure comes on. you may take it too far and have to edge back finer slightly, but this is the way i like to find the sweet spot for any given roast
for distribution of the grounds from the HG-1 you have the videos that Frans has already published in this forum - there are several actually. if you are using an electronic/doserless grinder my advice is fairly straightforward; dose to the centre of the portafilter to create a central cone, a mini volcano if you like. then use the edge of your tamper to cut the top off the cone and push it toward the perimeter of the basket. don't rush this step as i think it has a significant impact on the quality of the shot - i find the V2 LONDINIUM button tamper ideal for this. take care not to exert any downward pressure on the grounds whilst you are executing this step or it will be counterproductive - you are using the acute angle between the side and base of the tamper as a blade in effect to re-distribute the coffee around. then if you are running a deep straight sided basket with a large dose in it i personally recommend nutating to minimise the chance of channelling. we have described this action previously ad nauseam so i don't think we need to re-visit in detail here
If you have chosen to nutate you will now have a semi-compacted shallow angled cone of coffee grounds in the basket. The final step is to give the grounds a flat level tamp, which i like to deliver with a twist of the wrist and lift off
If you have chosen not to tamp it is the same step - a flat level tamp with a twist of the wrist and up
if you nutate you will most likely be able to grind fractionally more coarse
then when it comes to placing the portafilter into the group, and this is something i most definitely agree with the Italians on, the shot needs to be pulled immediately! don't fix the PF to the group and then waddle off and find a cup in the back of the cupboard or get the milk out of the fridge or send a text message: once the PF is affixed to the group that lever needs to be pulled! Why? otherwise the heat from the group dries out the coffee - the volatile oils in the coffee are driven off with heat very easily
in a similar vein, don't go to all the effort of a perfectly prepared basket and then ruin it all be clunking the PF against the group as you clumsily secure it to the group - a solid knock will completely disturb the puck and render all your hard work worthless
i hope these ramblings are of assistance in your pursuit to achieve a consistent rate of flow across the entire surface of the puck
areas of accelerated flow are quite easy to spot - they will be much paler in colour than the areas of the puck in which the water has moved through more slowly
if you have a single cone flowing into your cup but it is not centred on the bottom of the basket this is evidence that the flow is greater on the side of the puck that the off-centred flow has been pulled toward: this is a very important point to take on board. An even rate of flow on all 'sides' of the central cone that is falling into the cup below will by definition guarantee that the cone is centralised in the dead centre of the basket, i absolutely guarantee it
equally problematic are areas in the puck with zero flow - these appear as dry areas on the bottom of the portafilter. however these tend to be a result of higher flow in other areas of the puck - as soon as the water find an easier path to travel through the puck physics dictates that there is no chance that the water will try to work its way through the other areas of the puck
as a result where ever an area of high flow occurs in the puck the coffee surrounding that channel is chronically over extracted and tastes vile as in the worst cases almost all the water in the group flows through/over a very tiny number of the grinds in the puck, rather than flowing as evenly as possible over all the grinds in the puck and extracting only only a little, being the best and sweetest, from each individual grind in the puck. the rest of the puck has almost zero water flow through it and therefore all that coffee has almost no taste taken from it and is in essence, completely wasted
it isn't easy, and i don't think you should be disappointed if you don't achieve this level of execution every time, but if you understand the concepts at play and how to respond to them, then i think your results in the cup will consistently be an order of magnitude better
I can not stress enough how the taste of your espresso will improve exponentially of you make a disciplined effort to reduce the flow rate differential across the puck - we are not talking about 10% improvements here, we are talking about 100%, 200% improvements, orders of magnitude if you prefer, in particular with regard to the sweetness of the shot - the sweetness of the shot improves exponentially when you improve the uniformity of the flow rate across the puck
Now get a kilo of your favourite roast and pull back to back shots continuously in a single session until the whole kilo has gone and surprise yourself with the transformation in the cup
Most importantly bend down and learn to read the story that your naked portafilter is trying to tell you - it is trying to convey to you a wealth of information about all that is good and bad with how your have prepared the portafilter
Let me know how you get on
r.
These changes i never make lightly, so please understand that there is a strong driver behind it
I am writing this post just to make sure that you are letting your naked portafilter teach you about your espresso making technique
The point of offering naked portafilters is not so you can see the pretty patterns as the espresso flows from the portafilter; it really is to help you raise your performance
Until now it has been pretty chaotic getting this thing to fly - this is the first year where there is a bit more time to put the feet up and consider things, rather than being completely consumed with tactical responses to fast moving challenges
So an obvious benefit of a naked portafilter is it allows you to see what is going on, but we need to come back to that as you need to know what you are looking at in order to benefit from this
Second, the espresso is now falling directly from the bottom of the basket into your cup. This eliminates the possibility of taste degradation arising from a spouted portafilter that is not clean inside the pathway that the coffee travels along from the point it falls from the bottom of the basket until it drops from the bottom of the spout on the portafilter. That again is an easy to understand physical benefit
So, looping back to the key point, which is the ability to see the shot. Thats great, but now you need to know how to 'read' what you are seeing
Until now i have handed out 1 gram per second of espresso in the cup as a rule of thumb to get people underway
However, as some of you will have already discovered a simple rule like this does not protect you from differential flow rates at different places in the puck - it is merely an average and assumes that the difference in the rate of flow in different parts of the puck is not too great
But, what if that is not true? What if you have channelling? If you have heard of the term 'channelling' but have no idea what it might mean, there is a clue in the word itself - water that discovers an area of less resistance in a medium that it is flowing through will naturally channel or direct itself into that path of least resistance as the rate of flow is higher - this is basic physics at work
You see this effect at work in nature wherever water is being held back or dammed in some way: it all works well until the water manages to find a path of less resistance in the medium that is holding it back then the moment that the rate of flow increases in that path of less resistance the water scours out the media that is lying in that path of less resistance, which in turn allows even more water to flow down that path, which in turn scours out more and the rate of flow is all the time increasing. When it occurs in nature on a large scale the damaged to property and person is often catastrophic. When it occurs in your espresso puck the results are equally catastrophic, at least as far as your quest for exceptional espresso is concerned
The wonderment should not be directed at why your espresso does not always extract evenly, but rather that it ever extracts evenly at all. Be under no illusions, in deciding to make espresso you are picking a fight with physics. Once you understand that it is quite remarkable that forcing hot water through ground coffee results in an output that is drinkable
Another helpful point is not to view coffee grounds as scoria or rock or grains of sand that are to all intents non-permeable when water flows through them under pressure, but rather to think of coffee as a slightly coarse saw dust, for coffee is closest to wood in terms of its structure and how it performs when it comes into contact with water
So. What to do?
I think the easiest place to start with this topic is to consider what an 'perfect' extraction looks like, or in other words, an extraction where the rate at which the water flows through the puck is as uniform as possible at all points through the puck
It is important to understand that whilst the output from your grinder may appear uniform, it is not. The grains are all slightly different in shape and size
When we speak of distribution we are talking about arranging this mix of different sized and shaped coffee grinds as evenly as we can throughout the entire puck. That's right, its not easy, and the better the grinder the easier it will make this task for you, largely by delivering grounds of a more uniform size and shape
It is quite possible that you have never seen perfect yet, so you might have to imagine it for the moment, but i will try to deliver a video clip of a perfect start to a shot soon. in essence you can expect tiny tiny beads of espresso 'sweat' forming in the holes in the bottom of the basket during the pre-infusion phase which appear first near the outer perimeter of the basket then appear toward the centre. if you get coffee jetting out (spritzing if you are american) at this point, or even worse flowing out, the shot is a dud. release the lever gently and start again. assuming you don't get spritzers or coffee flowing during pre-infusion then at the end of your pre-infusion phase you can release the lever and as the pressure of the piston is exerted onto the water on top of the puck of coffee those beads of coffee sweat will quickly be on the move, being pushed out and then if the flow is roughly uniform across the entire surface of the puck they should be drawn toward the centre where they will form a single central cone and flow down into your cup
If you have made a reasonable start you will not get spritzers nor flow during pre-infusion but there is still a good chance that when you release the lever that you will be cursed with multiple streams flowing from the bottom of the basket. this is ok if you are just getting to grips with it, but for anyone who has had their machine for a while this is still a fail I'm afraid
The trick if you are at this what i call intermediate level of proficiency, and by the way i believe a lot of people are stuck at this level and have no idea how much hidden taste potential is locked inside their LONDINIUM I, you need to work on your distribution. Lets assume for the moment that you have a wonderful grinder and it is in no way to blame for this state of affairs, for it is completely within the realms of possibility to have what i call 'all the gear and no idea'
If your distribution is poor, particularly if you were experiencing spritzers or coffee flow during the pre-infusion phase it is very common to compensate for this by grinding finer. I am thinking in particular here of manual grinders, and to a lesser extent electronic or deserves grinders. Why? Because as annoyingly time consuming as they are to keep free of stale coffee the time honoured doser mechanism on a coffee grinder is actually hard to beat as far as nicely distributing the different sized and shaped grinds is concerned. Yes as fashionable as it is for speciality coffee types to mock the Italians because they don't take a refractometer to bed with them at night the Italians have some pretty trick engineering solutions across the board, not just in coffee technology, but the ubiquitous vaned doser mechanism is definitely one of their better ones - despite its shortcomings it does the job it was designed to do very well
conceptually i like to approach the challenge like this: for any given dose i like to grind as coarse as i can whilst still maintaining a uniform flow across the puck and hitting my target flow rate, so this could be 1g per second in the cup, or perhaps you might have a preference for a slightly slower (faster) flow rate; that is also fine - all you really need is a consistent methodology to resolve this issue as it is going to confront you every single time you make espresso. and at this point this is where i like to re-iterate the importance of sticking with one roast if your skills have you at this point on the espresso making curve. every time you change the roast you start solving this problem from scratch again. buy yourself a kilo (2 pounds stateside) of your favourite roast and just work it shot after shot, back to back, until the whole bag is gone. obviously you don't need to taste easy shot, or all of each shot, but if you taste part of the shots that you begin with and then part of the shots throughout the process, every fifth one that looks good perhaps, you will astound yourself with your rate of progress i absolutely promise you
as you eek ever so slightly coarser your poor distribution and or tamping will be guaranteed to result it spritzer, pre-infusion flows, and good old fashioned channelling once the spring pressure comes on. you may take it too far and have to edge back finer slightly, but this is the way i like to find the sweet spot for any given roast
for distribution of the grounds from the HG-1 you have the videos that Frans has already published in this forum - there are several actually. if you are using an electronic/doserless grinder my advice is fairly straightforward; dose to the centre of the portafilter to create a central cone, a mini volcano if you like. then use the edge of your tamper to cut the top off the cone and push it toward the perimeter of the basket. don't rush this step as i think it has a significant impact on the quality of the shot - i find the V2 LONDINIUM button tamper ideal for this. take care not to exert any downward pressure on the grounds whilst you are executing this step or it will be counterproductive - you are using the acute angle between the side and base of the tamper as a blade in effect to re-distribute the coffee around. then if you are running a deep straight sided basket with a large dose in it i personally recommend nutating to minimise the chance of channelling. we have described this action previously ad nauseam so i don't think we need to re-visit in detail here
If you have chosen to nutate you will now have a semi-compacted shallow angled cone of coffee grounds in the basket. The final step is to give the grounds a flat level tamp, which i like to deliver with a twist of the wrist and lift off
If you have chosen not to tamp it is the same step - a flat level tamp with a twist of the wrist and up
if you nutate you will most likely be able to grind fractionally more coarse
then when it comes to placing the portafilter into the group, and this is something i most definitely agree with the Italians on, the shot needs to be pulled immediately! don't fix the PF to the group and then waddle off and find a cup in the back of the cupboard or get the milk out of the fridge or send a text message: once the PF is affixed to the group that lever needs to be pulled! Why? otherwise the heat from the group dries out the coffee - the volatile oils in the coffee are driven off with heat very easily
in a similar vein, don't go to all the effort of a perfectly prepared basket and then ruin it all be clunking the PF against the group as you clumsily secure it to the group - a solid knock will completely disturb the puck and render all your hard work worthless
i hope these ramblings are of assistance in your pursuit to achieve a consistent rate of flow across the entire surface of the puck
areas of accelerated flow are quite easy to spot - they will be much paler in colour than the areas of the puck in which the water has moved through more slowly
if you have a single cone flowing into your cup but it is not centred on the bottom of the basket this is evidence that the flow is greater on the side of the puck that the off-centred flow has been pulled toward: this is a very important point to take on board. An even rate of flow on all 'sides' of the central cone that is falling into the cup below will by definition guarantee that the cone is centralised in the dead centre of the basket, i absolutely guarantee it
equally problematic are areas in the puck with zero flow - these appear as dry areas on the bottom of the portafilter. however these tend to be a result of higher flow in other areas of the puck - as soon as the water find an easier path to travel through the puck physics dictates that there is no chance that the water will try to work its way through the other areas of the puck
as a result where ever an area of high flow occurs in the puck the coffee surrounding that channel is chronically over extracted and tastes vile as in the worst cases almost all the water in the group flows through/over a very tiny number of the grinds in the puck, rather than flowing as evenly as possible over all the grinds in the puck and extracting only only a little, being the best and sweetest, from each individual grind in the puck. the rest of the puck has almost zero water flow through it and therefore all that coffee has almost no taste taken from it and is in essence, completely wasted
it isn't easy, and i don't think you should be disappointed if you don't achieve this level of execution every time, but if you understand the concepts at play and how to respond to them, then i think your results in the cup will consistently be an order of magnitude better
I can not stress enough how the taste of your espresso will improve exponentially of you make a disciplined effort to reduce the flow rate differential across the puck - we are not talking about 10% improvements here, we are talking about 100%, 200% improvements, orders of magnitude if you prefer, in particular with regard to the sweetness of the shot - the sweetness of the shot improves exponentially when you improve the uniformity of the flow rate across the puck
Now get a kilo of your favourite roast and pull back to back shots continuously in a single session until the whole kilo has gone and surprise yourself with the transformation in the cup
Most importantly bend down and learn to read the story that your naked portafilter is trying to tell you - it is trying to convey to you a wealth of information about all that is good and bad with how your have prepared the portafilter
Let me know how you get on
r.
Comments
I put a small mirror to check the extraction and to remove the bending from my espresso routine. It really helps to check for channeling and timing the pre-infusion time and the espresso flow.
I tried to 'catch' those moments in the video below. The flow could have been a little faster:
[video width=425 height=344 type=youtube]cieudclL7eI
Not when you use slow mo!
1. I don't usually see drips at the end of pre-infusion. The coffee appears immediately after I release the lever - should I be looking to achieve beads of coffee at pre-infusion stage?
2. I've always thought that if I see coffee at the edges first, then I have a donut extraction. I like to see coffee appearing at all points at the same time. What's the thinking behind it starting at the edges?
Hi,
I've always decided on a pre-infusion based on dose and roast level. I would then pull the shot regardless of whether I see drops or not. Should it be more a case of trying to achieve the desired pre-infusion time with spots of coffee appearing and adjusting grind until it's about right? i.e. if nothing appears after desired pre-infusion phase then I should coarsen the grind?
In the case, I can see a situation where the pre-infusion is right but then the shot runs too quickly. Maybe that would be poor distribution?
I think any variation can work as long as one is consistent and then change just one aspect at a time to look for improvement.
1. very very fine pin heads of brown appear in the holes in the bottom of the basket is what i mean
2. you are correct, but it is a matter of to what extent i think - its a donut extraction if it pours out at the perimeter with nothing in the centre, agreed. but in my experience you will generally find that although it takes less than one second to occur, as the pressure from the spring comes on the beading with start at the perimeter first and rapidly rush toward the centre. if you can get it to comes from all the holes all over the basket at exactly the same moment, thats even better