How to Make a Delicious Iced Latte: A Barista's Tutorial for Beginners

I wonder if you remember when you first had a latte. Perhaps many of you have long forgotten, but FrontStreet Coffee still remembers this vividly. The first sight of the delicate latte art was instantly captivating, a small sip revealed the subtle sweetness and bitterness from the crema, and by the second sip, the initial intense bitterness transformed into richness and smoothness, combined with the gentle sweetness of hot milk, creating a perfectly balanced sensation in the mouth, leaving a creamy chocolate-like aftertaste.

Just as the Western saying goes, "a thousand people have a thousand different Hamlets in their eyes," and the same applies to coffee. For what makes a good latte, perhaps everyone has their own standard answer. Some friends appreciate its generous portions, others are fond of its rich aroma and balance, while still others are fascinated by the exquisite latte art.

Conversely, when it comes to a bad latte, people's answers are remarkably similar—either the coffee is too bitter to drink, or it tastes too watery (thin) with no appeal, or worse, it's both bitter and watery. What causes this?

Latte Coffee Formula

FrontStreet Coffee's standard store configuration uses their own Sunflower·Warm Sun blend, which is medium-dark roasted and crafted to produce lattes with vanilla, creamy chocolate, and caramel cookie flavors.

Based on this, we first use the common espresso formula: a 1:2 coffee-to-liquid ratio, extracting approximately 2g of coffee liquid from 1g of coffee grounds, with a time between 25-35 seconds. For example, FrontStreet Coffee uses a double basket holding 20g of coffee grounds to extract 40g of espresso, with the time controlled between 27-33 seconds, and the entire extraction process should be normal (no channeling, spraying, or unstable flow).

For hot lattes, FrontStreet Coffee follows a 1:5.5 ratio, pouring 220ml of fresh milk into the milk pitcher and steaming it to 55-65°C with a foam layer of 0.3-0.5cm, then evenly combining it with the espresso in a ceramic cup and finishing with a properly formed latte art pattern.

For iced lattes, we use three ice cubes as a base, controlling the coffee-to-milk ratio at 1:5. First pour 200g of fresh milk, then drizzle 40g of espresso over it to preserve the beautiful layered effect.

Based on FrontStreet Coffee's experience, as long as the coffee beans and milk pairing are chosen appropriately, and the espresso extraction is consistently controlled with proper milk ratios, making a good latte is actually quite simple. In other words, if a latte tastes wrong, the problem must lie in these aspects mentioned above. Now, let's break them down one by one.

First, What Makes a Latte Too Bitter?

As we all know, without adding sugar, a latte is the least bitter among all flavored coffees because it's mixed with a large amount of milk, and the coffee flavor is often not prominent. When we do taste obvious bitterness, it indicates that the problem most likely lies with the espresso—either the coffee beans are roasted too dark, or the extraction parameters aren't correct.

Regarding the former, unless you're purchasing extremely dark roasted beans that are black and oily, most commercial espresso blends on the market typically use medium-dark to dark roasts to preserve more of the coffee beans' inherent flavors. At most, they're removed right at the second crack. Espressos made from these beans usually have rich crema, slight acidity, and moderate coffee bitterness, creating a compatible texture when balanced with milk that doesn't highlight any particular element.

Generally speaking, the "main culprit" that makes lattes bitter usually lies in the espresso extraction. The most common issues are too slow flow (extraction time exceeding 35 seconds with the above formula), channeling, or jetting streams that lead to over-extraction.

A customer once gave feedback to FrontStreet Coffee, saying that the lattes they usually make tasted quite good, but suddenly one day they became particularly bitter and not aromatic. The coffee beans were within their freshness period, extraction parameters and ratios were the same as usual, but they couldn't figure out what went wrong. After some inquiry, it was discovered that the used coffee puck had perforations, indicating channeling during extraction, possibly caused by clumped coffee grounds, leading to over-extraction and bitterness. In this case, the corresponding solution is to adjust the grind to be coarser, or use external force to break up the clumped coffee grounds.

What to Do When a Latte Tastes Too Watery or Weak?

From a barista's perspective, the richness of a latte is determined by two aspects: milk and espresso. For lattes, milk, which comprises the largest proportion, is naturally a key factor. If you want a rich and aromatic coffee, we recommend prioritizing whole fresh milk, because compared to UHT milk or skim milk, whole milk contains higher milk fat content, creates denser foam layers when steamed, has better stability, and provides a fuller texture for the coffee.

Actually, besides milk quality issues, under-extraction of espresso can also make lattes watery or weak. This situation often occurs with SOE (Single Origin Espresso). FrontStreet Coffee once used a lightly roasted Guji 8.0 to make an SOE latte. Despite reducing the milk proportion, the resulting texture was still incredibly bland, like a cup of hot milk with hints of citrus and caramel aroma. This was clearly due to insufficient extraction caused by the light roast level.

Therefore, when we use single-origin coffee beans featuring fruit-forward notes to make large-sized lattes, it's best to choose the corresponding SOE version to avoid "failures."

Why Would a Latte Be Both Bitter and Watery?

This situation is usually the opposite of the SOE cases mentioned earlier. It's often because the coffee beans are roasted too dark, giving the espresso an overall heavy and roasted character, with the latter part of the extraction predominantly featuring bitter, woody, and miscellaneous flavors. If extracted using a higher yield ratio, the espresso is very likely to become over-extracted.

For example, some people like to extract 40g of coffee liquid from 18g of coffee grounds, which results in a coffee-to-liquid ratio of approximately 1:2.22. This not only makes the coffee bitter and astringent, but the increased liquid weight also means higher water content, so the coffee concentration decreases, resulting in a latte that's naturally both bitter and watery.

If you feel that the lattes you make also have this contradictory taste, then try reducing the espresso extraction amount slightly, such as reducing the liquid weight by 5g to increase concentration. This not only avoids over-extraction but also makes the latte's texture fuller and richer.

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473