Espresso Flow Control Profiling

One of the most important features of the espresso machine. Maybe, the most important.

Contents:
THE BLOOMING PROFILE
THE RAMP DOWN (DECLINING, "SPRING LEVER") PROFILE
SOS - SAVE OUR SHOTS! CORRECTING GRIND SIZE ERRORS "ON THE FLY" USING PROFILING
TURBO SHOT
THE PLATINUM STANDARD: BLOOMING + TURBO + RAMP DOWN



The flow control does make a difference in extraction. Of course, good and freshly roasted beans are most important, but changing the water speed during extraction also greatly contributes to producing very tasty espresso. No esotericism - just the laws of physics at work.

Everyone knows that "the grinder is more important than the espresso machine" (C). I only agree with this as long as we're talking about machines with no flow control. However, I would prefer a Baratza Encore ESP and a machine with a paddle or dimmer to a $3000 grinder and a machine with a water debit I cannot change on fly.

Some people say flow control is unnecessary. It shows that they didn't even try to understand the subject.

Profiling is not very common for a few reasons:

• People don't know how dramatically it improves the taste.
• People mistakenly think profiling is hard to use.
• People mistakenly think that, to have profiling, they need a super-high-end machine, but they can install the FCD (Flow Control Device) on any machine with the standard (not modified) E61 group. Also, they can just install a cheap dimmer on many machines with a classic boiler (i.e. not with a thermoblock/thermocoil) to achieve the same goal (YouTube). If you're seriously considering a dimmer, it's best to go to a store that services and repairs espresso machines - so you don't harm your loved toy.

Now I'll talk about two profiles that have become a part of my routine seriously and for the long haul.

THE BLOOMING PROFILE

Enhances sweetness. Reduces sourness in light and medium roast. Improves the taste of beans roasted long ago and cheap beans. Prevents channeling.

It's a kind of advanced pre-infusion. The regular long pre-infusion ("Slayer shot") is uneven - the top layers are pre-infused much longer than the bottom layers (which are not pre-infused at all, in fact - once the water has reached them, the puck begins to resist and the main extraction starts). The blooming shot eliminates that unevenness, and also acts longer increasing the effect.

In addition, blooming is more convenient - you don't need to stare at the bottom of the basket, waiting for the first drops before you open the paddle (short pre-infusion finished before the first drops is not discussed at all - it's the king of unevenness!).

And you always start counting seconds from the same moment - when you see 35 sec on the timer. In contrast to that, the Slayer-style pre-infusion can have different length from brew to brew (for example, one time 15 sec, and the next time - 19 sec), so it's hard to calculate the brewing time looking at the timer (you need to add the desired time to another number each time).
Here's the blooming profile's algorithm (don't forget to grind a bit finer!):

• Start brewing with the faucet completely open.
• When 5 seconds are on the timer (strictly speaking, when the pressure in the group rises to 4 bar), completely shut off the flow.
• When 35 seconds are on the timer (i.e. 30 seconds of blooming have passed), open the faucet to the maximum (or to the pressure you want).
• Perform the usual extraction until the desired weight in the cup is reached.

In the following video, blooming starts not in 5, but in 10 seconds because the initial saturation of the tablet occurs at a limited flow, but I do not do so (the faster starts blooming, the less overall unevenness):



This profile contributes to a richer flavor because it increases extraction. Here's what it looks like numerically (from this video):



You can do blooming with the E61 even if it doesn't have FCD. However, using the E61 lever only is hard since it can take a few seconds to find the "pump off" position with no risk that the solenoid valve will destroy the puck. If you are too slow, the brewing will start rather than blooming. It's much easier to stop the flow with the paddle immediately after 5 seconds.

BTW...

If your machine has profiling (or the E61 group) but you for some reason don't use blooming, it can save the shot if the grind turned out to be too fine. If you start making espresso and find that the coffee is barely flowing out of the basket, immediately shut off the flow for half a minute to let the puck saturate, and then re-open the paddle. You'll see that the flow is faster! This will prevent (or at least reduce) over-extraction. I once grinded so fine that the coffee wasn't dropping at all. I immediately closed the valve for 30 seconds, and when I opened it again, the jet was there! This tip might be especially helpful when you've started new beans and don't yet know how to grind them.

THE RAMP DOWN (DECLINING, "SPRING LEVER") PROFILE

Increases body and richness, but prevents over-extraction. Reduces the bitterness of dark roasts. Improves the taste of blends. Removes the "stale taste" of beans roasted not recently. Prevents channeling.

Just close the paddle during the extraction:



The profile mimics a manual spring machine, where the pressure is decreasing naturally as the spring is relaxing. This leads to very tasty shots, which is why many people are fanatical about these machines and pay a lot of money for them. The following video shows how the pressure in a real spring lever (from the 1960s, BTW!) is dropping from 9.5 to 4.5:



You can restrict the flow either gradually or in 2-3 discrete steps. Or even in 1 step - like in the Slayer machine, whose paddle has 3 fixed positions: fully open, partially open (the "low flow" mode), and fully closed. So, strictly speaking, only the 1 step reduction has the right to be called a Slayer shot, not any ramp down! :-)

A SHORT PHYSICS LESSON

In the process of making espresso, more and more coffee substances (particles) end up in the cup, and accordingly, less and less of them remain in the basket. The puck gradually degrades and breaks down, becoming loose and porous. The same constant flow of water still continues, but over time the puck loses its ability to resist this flow as effectively as it did in the beginning. As a result, the coffee gets less and less extracted, and more and more just diluted with water, resulting in a less concentrated beverage - with weak body and taste.

The solution is obvious - gradually weaken the flow over the course of the brewing. This improves the taste in all roasts, but especially in dark beans, which are characterized by an easier (and therefore faster) extraction - ramping down significantly decreases bitterness.

RAMPING DOWN PREVENTS THE JET FROM BLONDING

When the pressure is gradually lowered, there is no blonding of the jet, which can be observed in this video. I never paid attention to this point before, but after the video I specifically checked - indeed, there is almost no blonding . The color changes from very dark brown in the beginning (almost black - because of the increasing extraction long "bloom") to medium brown at the end. However, the color never reaches not only yellow (as can be seen in many videos), but even a light brown.

Many people use jet blonding as an indicator that it's time to stop brewing. OMG! It's an indicator that it's time to buy a machine with profiling (or install an FSD or a dimmer)!

THE BREWING IS LASTING LONGER

Note that the pouring time of "lever" shots stretches to 35-40 seconds, which is longer than the classic 25-30 seconds. This is understandable - we want to pour the same amount of water (to get the same weight of the drink), but the flow gradually decreases. Look at the clip from the store where I bought my ECM Puristika. The dropping from 9.5 to 2.5 bar was 38 seconds:



And in the next video the shot lasted 45 seconds (from 12 to 1.5 bar):

SOS - SAVE OUR SHOTS!! CORRECTING GRIND SIZE ERRORS "ON THE FLY" USING PROFILING

The "aggressiveness" of applying the ramp down profile depends not only on degree of the roast but also on the grind size correctness. The profile is fantastic in fixing grinding errors:

• Too coarse - apply it immediately and aggressively. If you see the coffee jet flowing at breakneck speed, quickly move the paddle to a position near the full closing to extend the extraction time. In the following video, the man thus increased the extraction time to 27 seconds:
  
  
  
  
• Too fine - wait, and then decline slightly (if extremely fine - make a ristretto with no decline at all).

This means that the stepless grinder is less critical now. Mine (Niche Zero) is stepless, but I never go to half notches. Moreover, plus or minus two-three notches from the ideal setting don't kick me off from the zone of very taste espresso - I easily correct grinding errors with the paddle. This is very different from my previous Bezzera Duo DE, where the slightest deviation from the perfect grind size worsened the taste and there was no way to fix it. The degree of forgiveness of a machine with flow control is unprecedented - a bad shot is almost an impossible task. In fact, that is the classical reason why people love their fully manual toys. In our advanced times, this love is being transferred to pump machines with flow control. Caution: stay away from computerized machines on which it's not possible to change the flow rate manually once the brewing has started!

THE GOLD STANDARD

The combination of blooming and declining is considered by many as the "gold standard". The overall algorithm is simple and obvious: at the 35th second, after "blooming", fully open the flow, and then gradually decrease it.

I roast beans at home, but, for the sake of experimentation, I've made espresso with ordinary supermarket beans using the gold standard. The result was better than in many cafes where baristas use freshly roasted beans and high end espresso machines without flow control.

TURBO SHOT

More sweetness and clarity, the chocolate notes are strongly emphasized, the taste is as rich and intense as possible.

A funny thing happened to me once. After making a shot, I always stir my espresso with a very small spoon and then traditionally lick it (now you know my secret!). When I licked it after the first turbo shot I made, I was shocked - there wasn't much liquid, but the taste was so concentrated and sweet (almost sugary) that I thought it was ice cream or candy! No wonder the traditional 9 bar 25-30 sec espresso has tasted "like water" to me ever since, and I quickly gave it up in favor of the turbo.

The method was born from mathematical modeling by a group of scientists. It's based on the following two principles:

• 6 bar of pressure.
• The brew time is 15 seconds or even less (according to some sources, down to 7, but I would not go below 12). In some videos, the timeframe is extended to 20 seconds. In my experience, the ideal time in terms of taste is 13-15 seconds. The time is counted from the moment the coffee starts flowing from the basket (ha-ha, try a 7-second shot, counting from the moment the pump was turned on!).

These principles are respected through the adoption of the following measures:

• Coarser grinding. When coffee is ground fine, more acidic compounds are extracted, resulting in a sour taste. That's why the turbo is a great weapon to combat sour espresso!
• Smaller coffee dose (the common recommendation is 15 gr). I load 15-17 gr (instead of the previous 19 gr), depending on the beans.
• Greater brew ratio (the common recommendation is 1:3). I brew 34-40 gr (1:2 - 1:2.7).

The point is that high pressure hammers the puck compressing it into a brick. That makes it very difficult for the water to penetrate and pass through the coffee. The fine grinding contributes to this, as if turning coffee into cement. Through the fine dust, water is more difficult to seep even though the pressure, pushing it, is high. In this situation, the water has much more "reasons" to look for easy ways, i.e. to break through channels (and this is a direct way to lower overall extraction). It's not not necessarily large channels causing thin jets from the basket, or noticeable as light "emissions" at the bottom of the basket, or a "tiger color" jet that combines underextracted and overextracted streams - it can be a large number of microcracks, but the shot looks perfect and you get a lot of likes on YouTube. This is the reason why it is believed that the pressure should not exceed 9 bar (and we laugh at the "espresso machines" ads with 15 bar pressure). But it turns out that the 9 bar pressure is also too much.

There are two competing factors:

• The finer the grind, the larger the contact surface of coffee with water, so the more flavoring substances are "washed out" from the particles. This increases the extraction. However, a higher pressure is needed to push the water through the puck.
  
  
• The finer the grind and the higher the pressure, the more unevenly the water flows and the more "unaffected" (dry) areas remain (since a lot of water is moving through channels). This reduces the overall extraction, with the areas of the puck near channels being over-extracted.

Therefore, we must find a "crossover point" between these two factors - we should increase the pressure and decrease the grind size only until the harm from over-pressing begins to "outweigh" the benefits of fine grinding. A pressure of 6 bar and a flow time of 15 seconds is an excellent guideline for determining this point, found by scientific and experimental means, and repeatedly confirmed in practice (including by me).

You'll find many more intriguing details in the next two videos - by Lance Hedrick and James Hoffmann. All espresso lovers should definitely watch them!

Turbo is not a profile per se since it's not about changing the flow rate during brewing. So whatever you think about profiling (even if you're an ardent opponent!), try turbo now - it can be done on literally any machine! Change your OPV to 6 bar, and if that's impossible or difficult, achieve 6 bar by regulating the pressure with grind coarseness. The grind should be as coarse as possible, but fine enough to still accumulate 5.5 - 6 bar in the group. A shot of more than 18 seconds indicates that the grind is too fine. If you have flow control, then you can also try turbo by limiting the pressure to 6 bars with a paddle or dimmer.

THE PLATINUM STANDARD: BLOOMING + TURBO + RAMP DOWN

The turbo is cool on its own, but combining it with two the classic profiles improves the taste even more.

More often than not (unless I over roast) I do a turbo shot after a 30 second blooming. Of course, then the countdown of the seconds starts from the moment the faucet is opened after the blooming, when 35 seconds are on the timer.

But I am not brewing with constant 6 bar - most often after some time I slightly apply the "manual spring lever" profile. As a rule (with a perfect grind), I jump from 6 to 4 bar when 30 gr are the cup (ie, two-thirds). One step is enough since, on the turbo, the need to decrease the flow is clearly less - in fact, turbo is ramp down by itself compared with the classical 9 bar. By the way, the "one-step" flow restriction mimics the rump down profile as it's implemented in the Slayer machine.

In the beginning of my "love story" with turbo shots, this sometimes prolonged the extraction (after the bloom was finished) up to 25 seconds. But then I discovered that it tastes better if I grind even a little coarser than the turbo normally requires. So my pouring now lasts 15-18 seconds including ramp down - I turn off the pump when the timer shows 50-53 sec. Actually, my turbo shots last as long as they would have lasted without flow restriction, or just 2-3 seconds longer.