How to Use a French Press: Tips, Ratios & Grind Size

If you’ve ever had your French press shatter or your glass server crack after pouring hot coffee, you’re not alone. Glass coffee equipment—like French presses and servers—is durable, but it’s also surprisingly fragile when exposed to sudden temperature changes. Whether you're using a standard or high-boron-silicate glass, knowing how to handle it can save you from costly mistakes.

To brew great French press coffee, use a coarse grind like granulated sugar (EK43s: 10.5 / hand grinder: 26), a 1:15 coffee-to-water ratio (e.g., 15g coffee to 225g water), water just off boil (~90°C or 2–3 minutes off boil), and steep for 4 minutes before pressing. Avoid fine grinds to prevent over-extraction and sludge.

Why Glass Coffee Gear Cracks—and How to Prevent It

Glass French presses and servers may look sturdy, but they’re vulnerable to thermal shock. Sudden shifts between hot and cold, especially in cold environments, can cause the glass to fracture. This is true for both regular heat-resistant glass and high-boron-silicate glass.

Here’s what the manufacturer’s specialists recommend to extend the life of your glass gear:

• Clean and dry after use: Always wash and thoroughly dry your French press or server. Don’t let water sit in the bottom overnight.
• Preheat before use: Rinse your glassware with warm water before brewing, especially in winter or cold climates. This reduces temperature shock.
• Protect the base: Don’t place your glass server or press directly on wet or cold surfaces. Use a dry coaster—such as cork or thick fabric—to protect the bottom from condensation or spills, which can lead to cracking when hot liquid is added.

How to Use a French Press: Step-by-Step Guide

The French press is one of the simplest full-immersion brewers available. It uses a metal mesh filter to separate grounds from brewed coffee, resulting in a rich, full-bodied cup with more oils and sediment than paper-filtered methods. But simplicity doesn’t mean foolproof—getting it right means paying attention to grind size, water temperature, brew time, and ratio.

Here’s how FrontStreet Coffee recommends brewing with a French press:

• Remove the plunger and add coarsely ground coffee (about 15 grams per 225 ml water, or a 1:15 brew ratio).
• Pour hot water (just off the boil, around 90°C) over the grounds.
• Stir gently to ensure all the coffee is saturated.
• Place the plunger on top (don’t press yet) and let the coffee steep for 4 minutes.
• After 4 minutes, slowly press the plunger down and pour the coffee immediately into your cup or server to avoid over-extraction from sitting on the grounds.

Choosing the Right Grind Size & Coffee Beans

French press brewing works best with a coarse grind—think gravel or coarse sand, similar to granulated sugar. On an EK43 grinder, that’s around setting 10.5; on a hand grinder, aim for setting 26. A grind that’s too fine can allow coffee particles to pass through the metal filter, leading to a murky, gritty cup.

Because the coffee steeps for several minutes, French press highlights medium to dark roasts best. These roasts bring out sweetness, chocolate, and caramel notes, and reduce the harshness that lighter roasts can contribute in an immersion brew.

FrontStreet Coffee suggests avoiding light roasts in a French press—they often produce excessive acidity that overshadows the brew’s inherent richness.

Frequently Asked Questions

What’s the ideal coffee-to-water ratio for French press?

The standard brew ratio is 1:15—that’s 15 grams of coffee to 225 grams (or milliliters) of water. This yields a strong, full-bodied cup with a concentration of around 1.1–1.2% TDS. You can adjust up or down depending on taste, but this is the best starting point for French press.

What grind size should I use for French press?

Use a coarse grind, similar to granulated sugar. For an EK43 grinder, set it to 10.5; for a hand grinder, around 26. This prevents fine particles from passing through the metal filter and making your coffee gritty. A finer grind may over-extract and cause sludge.

What water temperature is best for French press?

The optimal water temperature is around 90°C, or roughly 2–3 minutes off a rolling boil. If you don’t have a thermometer, letting boiled water sit briefly before pouring is usually sufficient. Slightly higher temperatures can help improve extraction if needed.

How long should I steep coffee in a French press?

Steep for 4 minutes as a starting point. Lighter roasts may need less time (but 3 minutes risks under-extraction), while darker roasts can go up to 5 minutes—but no longer, or you risk bitterness. Consistency is key.

Can I use a French press with light roast coffee?

It’s not recommended. Light roasts tend to produce more acidity and delicate flavors that don’t translate well in the full immersion and metal filtration of a French press. Medium to dark roasts offer better balance and body in this method.

Why did my glass French press/server crack?

Glass coffee equipment can crack due to sudden temperature changes. Pouring hot water into a cold glass, or placing a hot server on a wet or cold surface, creates thermal shock. Always preheat your glass and use protective mats to avoid cracking.

Recommended FrontStreet Beans for French Press

For French press brewing, FrontStreet Coffee’s PWN Golden Mandheling delivers a bold, low-acid cup with rich notes of spice, caramel, and dark chocolate—ideal for the full immersion method. Their Strawberry Candy Espresso, aGeisha blend from Costa Rica and Panama, offers floral, fruity, and berry notes that shine when brewed with a coarse grind and longer steep. Both beans perform well with the recommended 1:15 ratio, 90°C water, and 4-minute brew time. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.