Lesson 2: The Essentials - Brew Ratio, Grind Size, and Water Temperature

From the KoffyKraft notes

Learning Goal

Learn the three fundamental elements of brewing: the coffee-to-water ratio, the grind size, and water temperature (plus brew time). Understand how these variables affect the taste of your coffee and how to get them "in the ballpark" for a good brew.

Core Concept Explanation

Every good cup of coffee balances several essential brewing variables. In this lesson, we focus on the most critical ones for a beginner:

Coffee-to-Water Ratio: This is the amount of coffee grounds used in relation to water. It's often expressed like "1:15" meaning 1 part coffee to 15 parts water. Using the right ratio ensures your brew is not too weak or too strong. The Specialty Coffee Association (SCA) recommends about 55 grams of coffee per liter of water (approximately 1:17.5 ratio) as an ideal middle point . A commonly used range is 1:15 (stronger) up to 1:18 or 1:20 (weaker) . At home, this means if you use 15 grams of coffee (roughly 1 tablespoon of whole beans is ~5 grams, though weighing is best), you'd use around 225 mL of water for a 1:15 ratio, up to 270 mL for 1:18. Staying in this range will generally produce a balanced cup. We also discuss using a scale to measure coffee and water - while you can brew by volume or scoops, using a simple kitchen scale will greatly improve consistency.

Grind Size: How fine or coarse you grind the coffee affects extraction speed. Finer grinds have more surface area and extract faster (and can easily lead to over-extraction if too fine), whereas coarser grinds extract more slowly. For example, a French press uses a coarse grind, while espresso uses a very fine grind. A good rule of thumb: if your coffee tastes weak or sour, the grind might be too coarse (try a bit finer next time). If it tastes bitter or harsh, the grind might be too fine (try a bit coarser). Remember: finer = more extraction, coarser = less extraction . At this stage, you don't need to perfectly dial in grind size - just aim for medium grind for general drip/pour-over brewing (similar texture to sand), and we'll adjust as needed in specific brew method lessons.

Water Temperature: Hot water is crucial for extracting coffee. The typical recommended temperature is around 195-205 deg F (90-96 deg C) for most brews, just off boiling. Boiling water (212 deg F/100 deg C) won't "burn" good coffee in most cases, but if you let water cool slightly off a rolling boil, you're usually in the ideal range. In practice, for a beginner, an easy method is: boil water and then let it sit for 30 seconds to a minute before pouring. That gets you roughly in the right zone. Using water that's too cool can result in under-extraction (weak, sour brew), because not enough compounds dissolve. Water that's too hot can sometimes pull out extra bitter compounds. We aim for that sweet spot in between.

These three factors - ratio, grind, temperature - along with brew time (which is naturally affected by grind and method) and a few others, make up the core "brewing variables." In fact, the SCA identifies coffee-to-water ratio, grind size, brew time, water temperature, turbulence (agitation), water quality, and filter media as the "Seven Essential Elements of Brewing" . Don't worry about memorizing them all now; as a beginner, the key is to get a feel for using the right amount of coffee, grinding it appropriately, and brewing with hot water. We'll introduce the other elements (like water quality and filters) as we go. By mastering the basics of ratio, grind, and temperature, you have the foundation needed for any brew method. Also, always remember to use fresh coffee - beans that were roasted recently (within a few weeks) and ground just before brewing. Freshness can greatly affect flavor; old pre-ground coffee often tastes flat or stale. Using fresh, quality coffee, along with these brewing fundamentals, will set you up for success.

Guided Exercise

Let's practice controlling these variables with a simple exercise:

Measuring Ratio: Take your coffee and measure out 15 grams (if you don't have a scale, use roughly 3 level tablespoons of whole beans). Boil some water and measure out 250 mL (about 1 cup). This is a ~1:16.6 ratio (15g coffee to 250g water), right in the recommended range. If you don't have a way to measure water in grams, you can assume 1 mL of water about 1 gram.

Grinding: Grind the 15g of coffee at a medium setting. If you don't have a grinder and are using pre-ground, that's okay for now (but consider investing in a burr grinder for fresher flavor). Note what medium grind looks like - roughly the texture of sand or coarse sugar.

Water Temperature: After your water boils, let it sit for ~30 seconds off the heat. This should cool it slightly from boiling. (If you have a thermometer, aim for ~200 deg F/93 deg C, but it's fine to do without one.)

Brewing Time (Immersion method for this exercise): Put your ground coffee in a large mug or jar. Pour the hot water (250 mL) over the coffee grounds. Start a timer (or note the time) and let it steep without stirring. You've essentially just made a very basic immersion brew (like a "cowboy coffee" without a filter). After 4 minutes, observe the brew. Most grounds will have sunk and some will float. Now gently smell and then carefully take a sip (it will be strong and have sediment, since we didn't filter - this is just a learning exercise, not a perfect cup to drink). Notice the strength and body.

Result: Pour the coffee through a simple kitchen strainer or cheesecloth into another cup to filter out most grounds, and taste it again. How does the strength feel? If it's extremely strong or bitter, you used a bit too much coffee or too fine a grind for that water amount; if it's very watery or sour, you might have under-dosed or the grind was too coarse. In our case with 15g in 250mL, it should be strong but drinkable. This exercise is to show how ratio, grind, and temp come together. You essentially brewed coffee by controlling those factors. Well done!

Quiz (Self-Check)

Check your understanding of the essentials:

If your coffee tastes too bitter and over-extracted, name two adjustments you might try next time.

What is an approximate water-to-coffee ratio range that usually produces good results?

Why is using water below 185 deg F (85 deg C) usually not ideal for brewing hot coffee?

Fill in the blank: A finer grind means ____ extraction (faster/slower and more/less?).

Answers

1. You could grind a bit coarser (reducing extraction) and/or use slightly less coffee or more water to weaken the brew. Also, you could slightly lower the water temperature or shorten the brew time - any of these would help reduce over-extraction. 2. Roughly between 1:15 and 1:18 (coffee:water by weight) is a common range for balanced brews (e.g. ~60g/L, plus or minus) . 3. If the water is too cool, it won't extract enough from the grounds - the coffee will likely taste sour, weak, or under-extracted because many flavor compounds, especially the enjoyable ones, dissolve best at higher temperatures. 4. A finer grind means faster and more extraction (water can extract flavors more quickly, so you have to be careful not to over-extract) . Conversely, a coarser grind means slower and less extraction.

Reflection

Think about the coffee-to-water ratio and grind you used in this exercise. How did the coffee taste? Write a few notes on whether it was too strong, too weak, or just right. Do you typically like a stronger cup or a milder cup? Reflecting on your taste preference will help you tweak ratios and grinds in future brews. Remember, there's no wrong preference - it's all about finding your perfect cup.