Moccamaster KBG 741 coffee machine test – as good as its reputation?

The Moccamaster has an almost legendary reputation. It is praised for its design, craftsmanship, durability, and coffee quality. This piqued our curiosity. We subjected the brewer to an intensive test, performing 40 brews with different coffees, brewing ratios, and quantities.

Our results are significantly more complex than the many positive online reviews. But first things first. As coffee makers, one thing is paramount to us: the quality of the coffee in the cup.

The following parameters are primarily responsible for this: the temperature of the brewing water, the distribution of the brewing water over the coffee, and the speed at which the coffee water is added.

The choice of coffee and grind size are important but cannot be influenced by the machine. Nevertheless, we provide tips for suitable coffees and an appropriate grind size.

Moccamaster Instructions – One Button for Coffee

Operating the Moccamaster KBG 741 is truly as simple as can be. Here, the Moccamaster hardly differs from most other filter coffee machines. Insert a filter bag, weigh the coffee, add water to the permanently installed water reservoir, and start with the push of a button. We wouldn't be the Kaffeemacher if we didn't refine these instructions.

We generally advise rinsing the paper filter thoroughly with hot water. This reduces the paper taste that would otherwise overpower the coffee later. A positive side effect is that the coffee filter paper then sticks better to the rim of the filter holder. This reduces the likelihood of the paper filter folding inwards and the water flowing past it. You can't rinse too much water, but 300 ml is a good amount.

Then add the correct amount of coffee grounds. The correct dosage depends on the desired beverage quantity. A good standard value is 60 grams of coffee per liter of water. We discussed this in more detail in a detailed blog post.

We first made two brews: 18 grams of coffee with 300 ml of water, and 60 grams of coffee with 1000 ml of water. The respective quantities were used, and we also weighed the water. We started the brewing process with the push of a button. We then compared the taste of these two brews.

18g and 300 ml vs. 60g and 1000 ml

In the comparative blind tasting of the two brews, the larger volume brew performed significantly better. Better, in this case, meant that the coffee tasted more balanced and homogeneous. It was also significantly stronger, i.e., more intense in flavor. The 18g/300g brew had a slightly unpleasant acidity and did not show the complexity and expected flavor notes of the coffee.

We adjusted the grind size for the 18g/300g slightly finer and performed further brews. However, the result did not significantly improve. As seen in Table 1, the strength, i.e., the concentration of dissolved coffee particles, was relatively low, averaging just over 1.0%. This value can be measured with a refractometer. A desirable result is around 1.1 – 1.5% strength (TDS = Total dissolved solids), with the rest of the beverage being water. Finer grind sizes usually increase resistance in the coffee, leading to slower drainage of the brewing water and thus more intense extraction. However, by refining the grind size, we could not achieve significantly stronger brews with the amount of coffee and water used.

Table 1.

The target extraction rate is 18 – 22 %. Extraction refers to the components extracted from the coffee bean. Higher extractions lead to a more pronounced strength in the cup. These two values are therefore interdependent (see also the blog post on Strength and Extraction).

Table 2 shows the results of the 60g/1000g brew. Here, we achieved stronger results with the same brewing ratio. The strength averages over 1.2% TDS, which is within the target range. Accordingly, the extraction is also within the target range for two out of five brews. In theory, we could have increased the extraction by using a finer grind size. However, the drainage in the filter was too slow, and the water level was at its maximum. A finer grind size would have caused the filter to overflow.

Table 2.

The comparison of the brews shows that the Moccamaster's extraction yield is better with a larger brewing volume. This is mainly due to the distribution of water over the coffee bed. With a larger brewing volume, the brewing water better covers all coffee particles and extracts them more effectively. This is primarily due to the design of the showerhead.

The Well-Intentioned Showerhead

Almost all classic filter coffee machines have the problem that the brewing water continuously drips onto the same spot in the coffee bed – usually right in the center. At this point, the coffee grounds are vigorously agitated with every drip and gurgle and thoroughly extracted by the constant inflow of water. Meanwhile, many other coffee particles on the edges of the coffee bed comfortably watch the extraction party in the center.

It doesn't take much to brew good filter coffee – except for even extraction. This is achieved when all coffee particles are in contact with water for an equally intense and long period as possible. Those who brew by hand practice this exact technique. Evenly moistening and agitating everything results in delicious coffee.

Moccamaster understood the principle and developed a bar-shaped showerhead with 9 holes. This is intended to distribute the brewing water over the coffee bed. Intended, because at least with the device we had, it doesn't work. The water flows into the brewing bar and a larger part of it drips out of the front holes. Ultimately, the location of the outflow is secondary, as the water below the showerhead combines into a single, connected stream.

We changed the incline of the brewing bar to rule out that this was due to a slanted tabletop or similar, but we always ended up with the same result.

As a result, the brewing water primarily extracts in the center, and a larger portion of the coffee bed is not evenly wetted. With larger water volumes – which is why the 60g/1000ml brew was better – this plays a minor role because a pool of water forms on the coffee grounds anyway. But even in this case, the extraction is not even.

This malfunction surprised us. The showerhead with multiple outlets shows the correct principle. However, the distribution of water is not pronounced enough to provide a significant improvement.

Improving Brews Through Agitation

If the showerhead doesn't work as it should, then the tricks of the hand brewer come into play. Simple stirring of the coffee after about 20 – 30 seconds of brewing leads to significantly better brewing results. If you stir again when the entire amount of water has been added, the brewing results are much more homogeneous and delicious.

Table 3

Table 3 also shows a significantly longer brewing time. This occurs because the entire coffee now creates resistance. By stirring at the end of the brewing, a rotation is specifically generated, which draws the coffee particles at the edge into a vortex and circulates them for a larger part of the brewing.

Moccamaster Brewing Temperature

Generally, the brewing temperature should be constant. Exceptions prove the rule. There are coffees that simply taste best when brewed at 80 degrees. In my filter coffee courses, I almost always do the test: the participants brew the same coffee at 50, 60, 70, 80, 90, and 100 degrees. There is a clear tendency that the coffee brewed at 90 degrees tastes best. Again and again, individual coffees also perform positively at other temperatures. A brewing temperature of 92 – 94 degrees is the most popular brewing temperature across all brews.

The Moccamaster brews very consistently – but slightly too high in temperature. It heats up incredibly quickly. Already with the first brew of the day, it is ready to brew after less than 20 seconds and drips the first drops of water onto the coffee.

We measured the temperature directly at the water outlet. The first surge of water dripped onto the coffee at a water temperature of 60 degrees. However, it was only a few milliliters, which probably cooled down due to heat exchange with the metal brewing rod. Subsequently, the Moccamaster brews very precisely and consistently at 98 – 99 degrees at the outlet throughout the entire brewing cycle. The impact temperature is hardly lower, as the showerhead is close to the coffee. In other words: the brewing temperature is very high – rather too high for many coffees. These high temperatures tend to intensify bitterness in coffee.

A brewing temperature of 98 degrees is definitely an option for very clear and light roasted coffees that inherently have little bitterness and are very transparent. However, for the vast majority of coffees, this temperature is too high. It becomes particularly critical for all coffees that are not specialty coffees and are roasted darker. Here, a brewing temperature of around 90 degrees or less would be the best choice.

Continuous vs. Pulse Brewing and Pre-infusion

The Moccamaster brews continuously from the first to the last drop. From the start of brewing, water is added in a steady flow. We tested the flow with the interesting Black Mirror scale. The scale actually consists of two scales. It measures the weight of the water added to the filter and, separately, the amount of brewed coffee already in the pot.

Continuous brewing is well-suited to deliver consistent results from one extraction to the next. Pulse brewing, also known as intermittent brewing, adds water in bursts. An initial burst is intended for pre-infusion, where only a small amount of water is added. The CO2 generated during roasting can escape. CO2 is not only unpalatable but its release also causes turbulence in the coffee bed. This "blooming" makes particular sense for darker roasts, as they contain significantly more bound CO2.

Another reason why we recommend using the Moccamaster primarily for lighter roasts.

The following graphic shows two brews that we recorded with the Black Mirror app. The left brew was made with the Moccamaster, the right one by hand.

Conclusion and Outlook Moccamaster KBG 741

We put the Moccamaster through its paces. The Moccamaster is the third filter coffee machine we have tested in a series of coffee makers. Our background is manual brewing. The author was Swiss Brewers Cup Champion (filter coffee champion) and multiple vice-champion. The demands on good filter coffee are high - but not that difficult to achieve. As mentioned at the beginning, a few basic parameters must be met.

We are dealing with automatic filter coffee machines because we expect that, in the future, the consistency across many consecutive brews can be better achieved by an automatic machine – with consistent quality.

The Moccamaster is not yet that machine. Compared to hand-brewed filter coffee, the Moccamaster delivers satisfactory to good results with light roasts and inadequate to satisfactory results with dark roasts.

Its temperature is very consistent – but unfortunately too high. The water distribution is well-intended but does not function adequately in practice. The biggest pro of the machine is its very good workmanship and the 5-year warranty.

These tests were performed with our test unit, which, like all other test units, we purchased.