This experiment started from a Facebook discussion in an espresso group about tamping vs tapping. The thinking was tamping compresses grounds at the top and the bottom more than the middle, and this is why one should use a heavy tamp. So I devised an experiment to better understand tamping.

该实验从一个意式浓缩咖啡小组的Facebook讨论开始，内容涉及夯实与敲击。 当时的想法是夯实压实顶部和底部的地面，而不是压实中间的地面，这就是为什么应该使用沉重的夯实器。 因此，我设计了一个实验以更好地了解捣固。

Short story: tamping affects the top layers more than the bottom layers with respect to compression. As tamp pressure increases, there is a diminishing returns on puck compression that is non-linear.

简而言之：就压缩而言，捣固对顶层的影响大于底层。 随着夯实压力的增加，冰球压缩的收益递减，这是非线性的。

Previous work has shown that tamping pressures at 5 lbs to 20 lbs doesn’t show a change in extraction. My own experience has been to greatly drop the tamp pressure, but I didn’t have an understanding on how pucks were compressed. I was also not able to find much information online.

先前的工作表明，在5磅至20磅的夯实压力下，抽提率没有变化。 我自己的经验是大大降低夯实压力，但是我对压缩球的压缩方式还不了解。 我也无法在网上找到很多信息。

So, I setup this experiment with a straight, clear tube and a scale to see how the grounds would compress. I used Kompresso for the tube because it has a clear, straight, and long with a plunger to fit. I put it on a scale that could go up to 5 kg, and I recorded a video as I pressed down.

因此，我用一个直的，透明的管子和一个秤来设置此实验，以查看地面如何压缩。 我使用Kompresso作为试管，因为它具有一个清晰，笔直且长的柱塞。 我把它放在可以重达5公斤的秤上，按下时录制了一个视频。

I did the collection twice because the first round had some trouble in being able to label the markings, but the second round went a lot better.

我做了两次收集，因为第一轮在标记标记上遇到了一些麻烦，但是第二轮进行得更好。

The two questions to resolve:

要解决的两个问题：

1. How does tamping affect the top, middle, and bottom of the puck?夯实如何影响冰球的顶部，中间和底部？
2. When does a harder tamp provide diminishing returns?什么时候进行更严格的篡改会减少收益？

数据采集 (Data Collection)

I put a small piece of paper after every 3g of coffee in the tube, but I aimed to keep the paper small. I didn’t want the piece of paper to affect how the coffee compressed. Putting the initial grinds in the tube did not cause compression as can be seen above.

在每3克咖啡中，我会在试管中放一小块纸，但我的目的是使纸变小。 我不想让那张纸影响咖啡的压缩方式。 如上所示，将初始研磨物放入管中不会引起压缩。

I took sample images at desired pressures, and then I lined them up with the starting image. I then used red lines for the starting positions and green lines for the ending positions.

我在所需的压力下拍摄了样本图像，然后将它们与起始图像对齐。 然后，我将红线用于起始位置，将绿线用于终止位置。

I wrote a simple script in Matlab to find the location of red and green lines in the images.

我在Matlab中编写了一个简单的脚本，以查找图像中红线和绿线的位置。

校准和标签 (Calibration and Labeling)

I also wanted to remove camera bias so I used a ruler to make a calibration image. I then marked it up with red lines and used the same script to find the locations of the red lines. I then fit a line to these markings and converted the line locations for each image to a physical distance.

我还想消除相机偏差，所以我用尺子制作了校准图像。 然后，我用红线对其进行了标记，并使用相同的脚本来查找红线的位置。 然后，我将一条线插入这些标记，并将每个图像的线位置转换为物理距离。

For each image, I was able to clearly get four lines for the slices of the Top, Middle, and Bottom. There was coffee above the Top and below the Bottom, but I can’t see the top, and I’m suspicious about using the bottom. I ended up using the three slices and the four lines (used to derive the slices) in analysis.

对于每张图像，我都能清楚地获得四行用于顶部，中间和底部的切片。 顶部上方和底部下方都有咖啡，但我看不到顶部，我对使用底部感到怀疑。 我最终在分析中使用了三个切片和四行(用于得出切片)。

The plunger is also smaller than a 58mm (58.5mm to be exact) filter basket. To accommodate, I scaled the pounds per square inch from the 0.93 square inches of the Kompresso tube to the 4.16 square inches of a 58 mm basket.

柱塞也小于58毫米(准确地说是58.5毫米)滤篮。 为了适应，我将磅/平方英寸的磅数从Kompresso管的0.93平方英寸缩放到58毫米篮子的4.16平方英寸。

夯实压力分析 (Tamp Pressure Analysis)

I plot here the slice height and then the height of the markers. I plotted the height of the markers in log to show they trend logarithmically. This means that to gain the same change in height change or compression, the force required grows exponentially.

我在这里绘制切片高度，然后绘制标记的高度。 我在对数图中绘制了标记的高度，以显示它们呈对数趋势。 这意味着，要获得相同的高度变化或压缩变化，所需的力将呈指数增长。

There is some noise in the data, but the trend is pretty clear. When looking at a line plot, we can see the trend is that the Bottom doesn’t compress like the Top and Middle. We can look at the percentage of compression with respect to the maximum compression achieved at 59 lbs.

数据中有些杂音，但趋势非常明显。 查看折线图时，我们可以看到趋势是底部不像顶部和中部那样压缩。 我们可以看一下相对于在59磅时达到的最大压缩率的压缩率百分比。

The Top compresses mostly in the first 6 lbs, and the middle is the slowest to compress. This makes sense because when you compress the grounds, there will be an equal and opposite force from the counter on the bottom grounds. In absolute values, the bottom is compressed less. This could be due to the paper marker moving when the grounds were put in. This experiment would work better if one set of grounds was colored and one wasn’t. My aim here was to get a quick experiment to see what it could tell me about tamping.

顶部的压缩主要在前6磅中，而中间的压缩速度最慢。 这是有道理的，因为压缩地面时，计数器会在底部地面上施加相等且相反的力。 以绝对值计，底部压缩较少。 这可能是由于插入地面时纸张标记器移动了。如果对一组地面进行了着色而没有对地面进行着色，则该实验会更好。 我的目的是进行快速实验，以了解夯实的知识。

比较切片 (Comparing Slices)

We can use the slice compression percentage and compare different slices. I did this by making a ratio of compression as seen below. The Top/Bottom ratio is the highest initially, which seems a bit obvious.

我们可以使用切片压缩百分比并比较不同的切片。 我通过如下所示的压缩率来做到这一点。 顶部/底部比率最初是最高的，这似乎有点明显。

Looking closer, the Top/Mid and Top/Bottom seem to even out while the Mid/Bottom stays below 1 which means that the Bottom compressed more than the middle.

仔细观察，“顶部/中部”和“顶部/底部”似乎平整，而“中部/底部”保持在1以下，这意味着底部的压缩程度大于中部。

专注于线标记 (Focusing on the Line Markers)

If we look at how much the line markers move as a percentage of their total movement or compression, we can see a little more on the middle. The Mid-Top and Mid-Bottom trend the same way. When comparing one layer to the next, they have close to a 1:1 ratio. However, when looking at the different lines vs the Bottom line, all the layers compress faster than the bottom up until 15 lbs. Then they are all fairly close (within 20%) to their maximum compression positions.

如果我们看一下线标记移动量占其总移动或压缩百分比的话，我们会在中间看到更多。 中上和中下的趋势相同。 将一层与另一层进行比较时，它们的比例接近1：1。 但是，当查看与底线不同的线时，所有图层的压缩速度都比底线快，直到15磅为止。 然后它们都非常接近其最大压缩位置(在20％之内)。

收益递减 (Diminishing Returns)

If we look at the overall height of the puck, the idea of diminishing returns is very clear. 80% of compression happened at 3 lbs of pressure. To get to 90% compression took 20 lbs, and then to get to 100% compressed took more than 50 lbs. 50% of all compression occurs in the first 1 lbs of pressure.

如果我们看冰球的整体高度，那么减少回报的想法非常明确。 80％的压缩发生在3磅的压力下。 要达到90％的压缩需要20磅，然后达到100％的压缩需要超过50磅。 所有压缩的50％发生在最初的1磅压力中。

I couldn’t get it to compress more than this point, and I wasn’t able to measure pressure past 13 lbs with this scale or the equivalent of more than a 60 lbs tamp for a 58mm basket. However, I doubt doing a 60 lbs tamp makes much of a difference. Previous experiments on tamp pressure showed there was no difference in extraction when comparing 10 lbs of tamp pressure t0 40 lbs. They didn’t go lower than 10 lbs though, so it is unclear.

我无法压缩到这一点以上，并且我无法使用此比例尺测量超过13磅的压力，或者无法测量58毫米篮子的超过60磅的夯实压力。 但是，我怀疑进行60磅的夯实会带来很大的不同。 先前的夯实压力实验表明，比较10磅夯实压力t0 40磅时，提取量没有差异。 它们的重量并没有低于10磅，因此目前尚不清楚。

In my own experiments, I’ve been reducing my tamp pressure to 1 lbs or less.

在我自己的实验中，我一直将夯实压力降低到1磅或更小。

A better experiment can be designed as a result of this one:

结果，可以设计出更好的实验：

1. Use two different colors of coffee grounds使用两种不同颜色的咖啡渣
2. Layer at 2g increments层以2g增量
3. Look at the compression.看压缩。

I am satisfied in now having a better understanding of our two questions:

我很满意现在对我们的两个问题有了更好的理解：

1. How does tamping affect the top, middle, and bottom of the puck?

1.夯实如何影响冰球的顶部，中间和底部？

Not evenly even at very high pressures.

即使在很高的压力下也不均匀。

2. When does a harder tamp provide diminishing returns?

2.什么时候进行更严格的篡改会减少收益？

Between 2 lbs and 3 lbs of pressure, there was a 20% increase in compression compared to the 10% between 3lbs and 20lbs or the 10% between 20lbs and 59 lbs. This means that most tamps heavier than 3 lbs should be similar, and that a massively heavy tamp may not be worth whatever effect it is having on the shot.

在2磅和3磅之间的压力下，与3磅和20磅之间的10％或20磅和59磅之间的10％相比，压缩率增加了20％。 这意味着大多数重于3磅的夯实图应该是相似的，而且沉重的夯实图不值得在镜头上产生任何效果。

If you like, follow me on Twitter and YouTube where I post videos of espresso shots on different machines and espresso related stuff. You can also find me on LinkedIn.

如果您愿意，请在Twitter和YouTube上关注我，在这里我会在不同的机器上发布浓咖啡拍摄的视频以及与浓咖啡相关的内容。 您也可以在LinkedIn上找到我。

我的进一步阅读： (Further readings of mine:)

Deconstructed Coffee: Split Roasting, Grinding, and Layering for Better Espresso

解构后的咖啡：焙炒，研磨和分层，以获得更浓的意式浓缩咖啡

Pre-infusion for Espresso: Visual Cues for Better Espresso

特浓咖啡的预输注：视觉提示可提供更好的特浓咖啡

The Shape of Coffee

咖啡的形状

To Stir or To Swirl: Better Espresso Experience

搅拌或旋流：更好的意式浓缩咖啡体验

Spicy Espresso: Grind Hot, Tamp Cold for Better Coffee

香浓意式特浓咖啡：磨碎热，捣碎冷可制得更好的咖啡

Staccato Espresso: Leveling Up Espresso

Staccato意式浓缩咖啡：升级意式浓缩咖啡

Improving Espresso with Paper Filters

使用滤纸器改善意式浓缩咖啡

Coffee Solubility in Espresso: An Initial Study

浓咖啡中的咖啡溶解度：初步研究

Staccato Tamping: Improving Espresso without a Sifter

Staccato捣固：无需筛分器即可提高浓咖啡

Espresso Simulation: First Steps in Computer Models

浓咖啡模拟：计算机模型的第一步

Pressure Pulsing for Better Espresso

压力脉冲使咖啡更浓

Coffee Data Sheet

咖啡数据表

Artisan coffee is overprice

工匠咖啡价格过高

The Tale of the Stolen Espresso Machine

被盗咖啡机的故事

Espresso filter analysis

浓缩咖啡过滤器分析

Portable Espresso: A Guide

便携式意式浓缩咖啡：指南

Kruve Sifter: An Analysis

Kruve Sifter：分析