Moccamaster KBG 741 Coffee Machine Test – As Good as Its Reputation?

The Moccamaster has an almost legendary reputation. It is appreciated for its design, craftsmanship and durability, as well as the quality of the coffee it produces. This made us curious. We put the brewer through an intensive test. We tested 40 brewing cycles with different coffees, brew ratios, and quantities.

Our results are significantly more nuanced than the many positive online reviews. But let's start from the beginning. As coffee makers, one thing is decisive for us above all: 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 flow rate of the coffee water.

The choice of coffee and grind size are important, but not controllable 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 really very simple. In this respect, the Moccamaster hardly differs from most other filter coffee machines. Insert filter, weigh coffee, pour water into the permanently mounted water tank, and start with the push of a button. We wouldn't be coffee makers if we didn't refine these instructions.

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

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

We first did two brewing cycles. 18 grams of coffee with 300 ml of water and 60 grams of coffee with 1000 ml of water. Each quantity was added. We also weighed the water. We started the brewing cycle by pressing a button. We compared these two brewing cycles by taste.

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

In the comparative blind tasting of the two brewing cycles, the brewing cycle with the larger volume performed significantly better. Better, in this case, meant that the coffee tasted more balanced and homogeneous. It was also noticeably stronger, more intense in flavor. The 18g/300g brewing cycle had, on one hand, a slightly unpleasant acidity and, on the other hand, lacked the complexity and expected flavor notes of the coffee.

We adjusted the grind size of the 18g/300g somewhat finer and performed further brewing cycles. However, the result did not improve significantly. As you can see in Table 1, the strength in particular—that is, the concentration of dissolved coffee particles—was relatively low at just over 1.0% on average. This value can be measured with a refractometer. A desirable result is approximately 1.1–1.5% strength (TDS = Total Dissolved Solids), with the rest of the beverage being water. Typically, finer grind sizes increase resistance in the coffee, which leads to slower water flow and thus more intensive extraction. However, we were unable to achieve significantly stronger brewing cycles by refining the grind size with the coffee and water quantities used.

Table 1.

The target extraction is 18–22%. Extraction refers to the proportion of the coffee bean that is removed. If higher extractions are achieved, the strength in the cup is also more pronounced. These two values are therefore dependent on each other (see also blog post on strength and extraction).

Table 2 shows the results of the 60g/1000g brewing cycle. Here we achieved stronger results with the same brewing ratio. The strength is on average over 1.2% TDS and thus within the target range. Correspondingly, extraction is within the target range in two of five brewing cycles. In theory, we could have increased extraction with a finer grind size. However, the drain in the filter was too slow and the water level was at maximum. A finer grind size would have caused the filter to overflow.

Table 2.

The comparison of the brewing cycles shows that the extraction yield of the Moccamaster is better with larger brew volumes. This is primarily due to the distribution of water over the coffee bed. With larger brew volumes, the brewing water better contacts all coffee particles and washes them out more effectively. This is mainly due to the design of the brew head.

The Well-Intentioned Brew Head

Almost all filter coffee machines of the classic design have the problem that the brewing water continuously drips on the same spot in the coffee bed—usually right in the center. At this spot, the ground coffee is heavily agitated with each drop and bubble and intensively extracted by the constant influx of water. Meanwhile, many other coffee particles at the edge of the coffee bed sit back comfortably and 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 as many coffee particles as possible are in contact with water equally intensively and for the same length of time. Anyone who brews by hand practices exactly this technique. Evenly saturate and agitate everything—that makes delicious coffee.

Moccamaster understood the principle and developed a rod brew head with 9 holes. This is supposed to distribute the brewing water over the coffee bed. Supposed to, because at least with the device we have, it doesn't work. The water flows into the brew rod and drips out mostly from the front holes. Ultimately, however, the location of the outlet plays a minor role because the water below the brew head combines into a single, continuous stream.

We changed the incline of the brew rod to rule out that it might be due to a slanted table top or similar, but we always ended up with this result.

The consequence is that the brewing water is extracted predominantly in the center and a larger part of the coffee bed is not evenly saturated. With larger water quantities—that's why the brewing cycle with 60g/1000ml was better—this plays a minor role because a water bed forms on the ground coffee anyway. But even in this case, extraction is not even.

This malfunction surprised us. The brew head with multiple outlets shows the right principle. However, the distribution of water is not pronounced enough to bring about a significant improvement.

Improving Brewing Through Agitation

When the brew head doesn't do what it should, the tricks of manual brewing come into play. Simply stirring the coffee after about 20–30 seconds of brew time leads to significantly better brewing results. If you repeat the stirring once all the water has been added, the brewing results are significantly more homogeneous and more delicious.

Table 3

Table 3 also shows a significantly longer brew time. This occurs because all the coffee now creates a resistance. By stirring at the end of the brewing cycle, rotation is deliberately generated, which picks up the coffee particles at the edge into a vortex and keeps them spinning over a larger part of the brewing cycle.

Moccamaster Brew Temperature

Basically, the brew 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: participants brew the same coffee at 50, 60, 70, 80, 90, and 100 degrees. There is a clear tendency for the coffee to taste best when brewed at 90 degrees. Again and again, individual coffees also turn out positively at other temperatures. A brew temperature of 92–94 degrees is the most popular brewing temperature across all brewing cycles.

The Moccamaster brews very consistently—but slightly too high in temperature. It reaches temperature incredibly quickly. Already on the first brew of the day, it is ready to brew in less than 20 seconds and the first water droplets drip 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, this was only a few milliliters, which were probably cooled by heat exchange with the metal brew rod. Subsequently, the Moccamaster brews very precisely and consistently at 98–99 degrees at the outlet throughout the entire brew cycle. The impact temperature is hardly lower because the brew head is close to the coffee. In other words: the brew temperature is very high—too high for many coffees. These high temperatures tend to intensify bitterness in coffee.

98 degrees brew temperature is certainly an option for very clear and lightly roasted coffees that inherently carry little bitterness and are very transparent. For the vast majority of coffees, however, this temperature is too high. It becomes particularly critical for all coffees that are not specialty coffee and tend to be darker roasted. Here, a brew temperature of around 90 degrees or lower would be the best choice.

Pulse vs. Continuous Brewing and Pre-Brewing

The Moccamaster brews continuously from the first to the last drop. Once brew starts, water is added in a steady flow. We tested the flow with the interesting scale from Black Mirror. The scale actually consists of two scales. It measures, on the one hand, the weight of the water being added to the filter and, on the other hand, the amount of brewed coffee already in the pot.

Continuous brewing is well suited to deliver consistent results from brewing cycle to brewing cycle. Pulse brewing, also called bloom brewing, adds water in pulses. The first pulse is intended as a pre-brewing phase. In this phase, a small amount of water is added. The CO2 created by roasting can escape. CO2 is, on the one hand, not delicious and, on the other hand, its escape causes agitation in the coffee bed. This so-called blooming is especially useful for darker roasts, as they have much more CO2 bound.

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

The following graphic shows two brewing cycles that we captured with the Black Mirror app. On the left is brewed with the Moccamaster, on the right by hand.

Conclusion and Outlook Moccamaster KBG 741

We examined the Moccamaster thoroughly. The Moccamaster is the third filter coffee machine we test in a series of coffee machines. Our background is manual brewing. The author was Swiss Brewers Cup Champion (Filter Coffee Champion) and multiple runner-up. The standard for good filter coffee is high—but not that difficult to achieve. As mentioned at the beginning, only a few basic parameters need to be met.

We deal with automatic filter coffee machines because we expect for the future that, in particular, the consistency across many brewing cycles in succession can be better achieved by an automatic machine—with consistent quality.

The Moccamaster is not yet this machine. The Moccamaster delivers satisfactory to good results compared to hand-brewed filter coffee for light roasts and poor to satisfactory results for dark roasts.

Its temperature is very consistent—but unfortunately too high. The water distribution is well-conceived but doesn't function adequately in practice. The machine's greatest advantage is its excellent build quality and 5-year warranty.

These tests were performed with our test device, which we have purchased, like all other test devices.