Can You Use Milk to Brew Pour-Over Coffee? What Temperature Should Milk Be for a Latte? How to Add Milk to Pour-Over Coffee and What's the Ratio?

Pour-Over Coffee: An Introduction

Pour-over coffee is a drip-style coffee extraction method. The so-called drip method means that as water is poured for extraction, coffee simultaneously drips out. Because pour-over equipment is affordable and easy to use, it has become a common coffee brewing method for many people at home.

The Question of Milk in Pour-Over

However, inevitably, after drinking too much black coffee, one might want to change flavors. For example, a rich and creamy milk coffee. But unfortunately, pour-over coffee with added milk tends to taste watery. This leads many people to wonder: "Can pour-over coffee be brewed directly with milk?"

The Short Answer and Three Challenges

Emmmmmm... Let's start with the conclusion: If you're just using milk for brewing without concern for taste, yes, it's possible. After all, milk is also a liquid, so it's not impossible! However, if we want to extract a "delicious" and "tasty" cup of coffee using milk, we need to solve three problems! If these can't be resolved, the extracted coffee will be difficult to make enjoyable.

Problem 1: Milk Temperature

The first problem is milk temperature. As we all know, the reason why pour-over coffee is popular, besides being able to produce a cup of coffee with clear flavor profiles, is because it's fast! It only takes about 2 minutes to extract a pot of black coffee with outstanding flavors. Achieving this "feat" depends on the combination of various extraction parameters. Take light roast coffee as an example: to extract a large amount of flavor from light roast beans in a short time, we need to use fine grinding, extremely high water temperature, and water flow agitation to achieve our goal. Even easily extracted dark roast beans require water temperatures starting from 86°C for extraction.

However, milk cannot reach such high temperatures. We know that once milk exceeds 70°C, components like protein and lactose inside will be damaged by high heat. The consequence of these substances being damaged is that the milk's texture becomes worse and thinner, with reduced sweetness. Simply put, the milk becomes less enjoyable! Therefore, to maintain the "integrity" of milk, we need to control its temperature below 70°C. Under this limitation, milk is merely warm and slightly hot, with low extraction efficiency. If we brew directly like this, obviously, you'll only get a coffee-flavored milk rather than a milk coffee. Of course, many clever people might think of adjusting other extraction parameters to compensate, such as grinding finer or extending extraction time.

The idea isn't wrong, but due to the significant temperature difference, even with adjustments, milk can hardly extract all the substances from coffee as we'd like. And this is just the first problem. Next, FrontStreet Coffee will discuss the second problem faced when using milk to extract coffee: oversaturation.

Problem 2: Milk Composition

Then comes the second problem: milk composition. Good! Let's assume milk can be heated to 92°C. But we need to know that not all liquids are suitable for brewing coffee, and even water is no exception. FrontStreet Coffee shared previously that to brew a delicious cup of coffee, besides ensuring the quality of coffee beans, the choice of water is also very important. Although water is colorless and tasteless and seems to contain nothing, it actually contains many substances, such as ions like calcium, magnesium, potassium, sodium, and bicarbonate ions. The amount of these substances in water affects its hardness and softness, while also determining how easily water can dissolve coffee substances.

The SCAA's recommended TDS standard for coffee brewing water is 75-250ppm (the content of these substances in water), but in reality, water that easily produces delicious coffee typically has a TDS below 100ppm. Why? Because the amount of substances in water determines how easily it can dissolve coffee substances. An appropriate amount of substances helps dissolve flavor compounds, while too few or too many substances make it difficult for water to extract coffee substances. The more substances in water, the harder it is to dissolve coffee substances because the water gradually approaches saturation. This principle applies to other liquids as well. And milk... let's sacrifice TDS for a moment and measure it!

Squinting and looking, it's over 200ppm, which is okay, milk barely meets extraction standards. But when we look closely!!

It's over 200 × 10!!! And that's the fact—milk contains extremely rich substances. Compared to water which has almost nothing, using milk for perfect extraction is obviously much more difficult.

Problem 3: Filtration Speed

Finally, the third problem: filtration speed. Because milk contains extremely rich substances, besides extraction, we face another problem: extremely slow filtration speed. FrontStreet Coffee occasionally shares cold brew coffee made with milk, and friends who have tried following the articles know that during filtration, milk's permeation speed is extremely slow. While pour-over isn't as extreme, it's still very slow. Because of the high substance content, the speed of permeating through high-precision filter paper naturally slows down. FrontStreet Coffee has conducted many extraction attempts with milk, mainly using 15g of coffee powder extracted with 225ml of milk, and it takes an average of 5 minutes (or more) to completely filter one pot.

Although it continues to drip during the process, due to the excessive time, this is no different from immersion brewing. In fact, it's not as simple and convenient as immersion brewing. Most importantly, the extracted milk coffee doesn't taste good—it's all under-extracted! This is why FrontStreet Coffee gave such a definitive answer in the first problem. Therefore, due to these three limitations (mainly the first two), milk is not suitable for pour-over coffee brewing. Although the flavor is strong, due to insufficient extraction efficiency, it basically has negative tastes of bitterness, sourness, and astringency—unpleasant to drink! However, if you really want to drink rich milk coffee extracted with milk, FrontStreet Coffee would recommend using long-steep cold brew, which would be more appropriate. You can learn more by moving to this article → "Milk Extracted Coffee."

Final Considerations

Finally, FrontStreet Coffee does not recommend friends trying to brew by putting milk in a pour-over kettle at home, as this will face a rather difficult problem! What problem? The pour-over kettle is hard to clean!!!!!!!

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