Analysis of coffee from used espresso bud


Before I tell you what to pay attention to, there are a few things you don't need to pay attention to. Some may surprise you, but they don't really matter.


New baristas are probably freaked out by a muddy puck in the lever, thinking it's a harbinger of bad espresso, but that may not be true at all. Youcan have a great espresso from a muddy puck, or you can have a bad espresso from a perfect puck.

So why does this happen? You need water to make espresso. It goes from the pump to the boiler and from there to the head, where it flows through the shower to the compressed coffee in the portafilter. It then starts to seep into the coffee and move through it until we start to get the espresso we've been waiting for all along. At the stage where water is everywhere, above the coffee, in the coffee and below the coffee and you stop the extraction, a valve opens at the back inside the machine to release the pressure. There's nothing pushing the water, so it doesn't have much room to escape and it stays on the coffee bud.

If you quickly release the portafilter lever after extraction, you'll find a puddle of water that slowly sinks into the ground coffee. After a few seconds, the water is absorbed into the coffee.

The bigger the gap between the ground coffee and the shower head of the machine, the more water will get in. The more water there is, the wetter and muddier your coffee bud will be.

Using the right basketis also a solution . The best choices are the so-called VST baskets, which are taller than the others. This will ensure that your compressed coffee doesn't rub against the shower head of the machine, as a certain gap is needed. Because if there is a missing a, uneven extraction can occur, which is much worse than water in the coffee bud.

The packed coffee shouldn't be right up to the rim, rather the opposite, there needs to be a smaller gap between the coffee and the rim. This will ensure that the shower head doesn't break the coffee bed and the espresso is properly extracted. Source: Rob Wicks |


Every barista has a different opinion on this, some say it is important for extraction how muchpressure you create when tamping some say it is not. After some testing, however, it has been concluded that it doesn't really matter that much. The action of the tamper on the coffee while tamping slows extraction only very slightly. However, you still can't underestimate tamping because what is important is correct and even alignment. If you find that the espresso doesn't taste as it should according to the recipe, check that you have the right grind, the right amount of coffee or even how fresh the coffee is.


Last in the category of non-essentials is the notch in the portafilter basket. Many portafilter baskets have a small indentation visible on the inside, which some intuitively think of as a sort of maximum fill line or dosing aid.

In reality, the indentation simply helps the basket fit better into the portafilter. When choosing the right basket, like the VST, people often ask what the difference is between the version with and without the torsion and whether it has any effect on extraction. A basket without vryp simply lacks vryp, nothing more. Some prefer the basket without the notch because it is easier to insert and remove from the portafilter. Others believe it might produce a more uniform flow. However, no difference in extraction with and without the notched basket was noted.


Now that I've eliminated all the non-essential possibilities, let's look at what can tell us whether or not the espresso is good.


As I mentioned earlier, t ampingtechnique and distributionis not as important as tamping pressure . Ensuring the coffee is evenly distributed across the surface of the portafilter basket, the coarseness of the grind, and making sure your tamp is nice and even will have a huge impact on extraction. Coffee distributors and automatic tampers can be great helpers in this case.

A bad tamper is also great to spot on an espresso puck. Theexperiment of Nikolai Fürst, a Colombian roaster and coffee coach ,serves as an example . He deliberately prepared several espressos with an uneven coffee bed by pushing the coffee to one side of the basket before tamping. He also varied the coarseness of the grind. After extraction, there were no depressions or changes in bud structure visible on the buds. However, when they tipped the buds, they noticed that wherever the coffee bed was thickest, dark spots appeared on the bottom of the bud .

Similar dark spots also appeared on the bottom of each bud formed with very fine grinding or weak extraction. These are therefore coffee particles which have not been extracted because of the thick layer. In the same places as the spots on the bud, grease spots were also observed on the filter baskets. This suggests that thedark spots contain coffee oils or colloids that remained in the bud because the water flow was too slow to carry them out of the bud.


Next, make sure you are using thecorrect amount of coffee for your cup size. Although you'll often hear ,,single'' or ,,double'', many cups have a designated batch weight. Generally it's 7 grams for a single cup, 14 grams for a double cup. However, you can also find 17 or 21 gram coffee baskets on the market. However, it is always necessary to keep the correct amount and not try to put more coffee in a smaller basket or only half in a larger one. A variation of more than one gram can cause very inconsistent results.

Using the correct cup size goes hand in hand with the quantity used, as does the coarseness of the coffee. However, coarser grinds will not save a larger cup size, so use more coffee and make more espresso.


Another important thing to look out for ischanneling. Any sign of channeling will give you a clue as to what is happening inside the bud during extraction. The surest way to detect this is to look at the underside of the portafilter while your espresso is being extracted. Splashes, pauses in extraction, and the way the first drops pass through the filter can be warning signs.


Although this entire article is about how to tell the quality of an espresso from the coffee bud without tasting it, I have to admit thattaste will still tell you the most. And that's mostly because your tongue is a hyper-sensitive tool that can detect subtle chemical differences. All the other details you may observe during or after preparation are just steps on the way to trusting that you are serving the customer a good coffee.


Preinfusionis another thing that can help you to be sure of a properly prepared espresso . This can be encountered in both espresso and filter coffee preparation. It helps reduce channeling and improves the evenness of the extraction. In espresso preparation, preinfusion also reduces the movement of fine particles. Ideally, espresso preinfusion takes place at zero pressure and low flow rate (approximately 2 to 3 ml/s) and the pressure is not increased until the entire coffee bed is moist.

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