Solving Bitterness in Cold Brew: 9 Tips for a Smoother Sip

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Cold brew coffee is often praised for it’s smooth, less acidic flavor but maybe you brewed it at home and wondered why the cold brew from the coffee shop or the grocery store tastes smoother?

The key to avoiding a bitter cold brew is to understand what causes it. Often, it’s the result of over-extraction, which can be caused by steeping too long or using too fine coffee grounds.

With a few science-backed adjustments you can brew a perfectly balanced cold brew every time.

Here are 9 actionable tips to help you avoid bitterness.

Choose Coarse Coffee Grounds

Grind size matters in cold brew. Fine grounds have more surface area in contact with the water which means the flavors extract quicker.

Coarse ground coffee is the size and texture of kosher salt or raw sugar. You can buy coffee that is specifically ground for cold brew, or grind it yourself using a burr grinder.

Burr grinders create a more consistent size. Blade grinders can result in coffee with a range of sizes, including some finer particles.

Why it works: Using coarse grounds reduces the surface area of coffee in contact with that water, which prevents over-extraction during the long steep times of cold brew coffee. As a bonus, coarse grounds are easier to strain out, which means less sediment in your coffee.

Double check your coffee to water ratio

One of the more confusing aspects of cold brew is ratio, because scientists report it in weights. According to researchers the ratio for cold brew is anywhere from 1:4 to 1:10.

A ratio of 1:6 (by weight) should give a balanced brew. If you want to make a concentrate, try 1:4 by weight.

To do this, get out your scale and weigh your coffee (let’s say 20 grams) and then weigh out 80 grams of water for a 1:4 ratio, or 120 grams of water for a 1:6 ratio.

While I always think it is better to err on the side of too strong (because it is easier to fix than a brew that is too weak), if you find that your cold brew is bitter and you are using the right grind size, try adding a little more water to your next batch and see if that helps.

Why it works: just like fine coffee grinds results in over-extraction, so can having too much coffee in your water.

Reduce your steeping time

Hot coffee can be made in minutes because hot water is great for releasing the flavor compounds for coffee. With cold brew, we need to let the water contact the coffee for a longer period of time because cooler water is not so efficient in extracting the flavors from coffee.

The recommended steep time according to researchers is 12-16 hours. Personally, I find success in steeping 14-20 hours.

If you are brewing for more than 20 hours, try reducing your steeping time by a couple hours. Keep doing this until you find your sweet spot.

If you are brewing less than 12 hours, try adding time. Under-extracted coffee doesn’t taste great either.

Why it works: over-extraction is a common cause of bitterness and steeping too long is one common cause (not using coarse coffee is the other main cause, see #1 above).

Experiment with different beans

The two main factors to look at are origin and roast level. When it comes to bitterness, roast level matters more.

Medium roasts work well in cold brew. Dark roasts can work, but may have a smokier, more “burnt” taste that can be perceived as bitterness.

You can also experiment with lighter roasts, which can have sweeter, fruitier, more acidic notes.

Try choosing beans for Central or South America. This is what many commercial cold brew makers are using.

Or, ask your local coffee roaster for a recommendation.

Why it works: a lot of the coffee’s flavors are determined by how it is roasted. Change your coffee, change your flavor.

Try steeping at room temperature

Cold brew can be made at room temperature (about 68-72 F) or cooler. Personally I prefer to brew in the fridge for food safety reasons, but we are getting to the part of this list where we are making minor tweaks.

Why it works: The cooler the water, the slower the extraction. In the fridge you may actually be under-extracting your coffee, which can taste less smooth and bold.

Dilute to taste

Adding water or other additives can take the edge off of a bitter coffee, especially one that tastes bitter because it is too strong.

Dilute your cold brew with water, milk, or a milk alternative. You could also experiment with creamers or sweeteners.

Why it works: If your coffee is bitter because it was brewed too strong, diluting it with water can take the edge off but won’t change a bitter flavor. Using milks or sweeteners can mask the bitterness.

Filter and strain completely

Coffee grounds continue to be extracted if not removed from your brew. This sediment is very fine and can release bitter compounds.

Be especially aware of this when using a French press (with coffee grounds trapped under the plunger but still in contact with the water) or a cold brewer with a mesh filter, which can allow fine sediment to pass through.

The most thorough filtration is through a paper coffee filter. This stops extraction in its tracks. The only downside is it also traps some of the coffee oils which can affect body or mouthfeel, making your coffee taste thinner.

Why it works: Leftover sediment continues to be extracted. Over extraction leads to bitterness.

Let it mellow

This one is not research backed, but from my own observation. My cold brew always tastes better on the 2nd day. Try making a batch big enough for two days and compare your impressions between day 1 and day 2.

Why it works: I don’t know 🙂

Keep notes & adjust next time

Finding the perfect cold brew can be highly personal. It’s all about what tastes best to you. Keep a tasting journal and keep a record of your experiments, tracking details like:

Coffee-to-water ratio
Steep time
Roast level
Beans used
Grind size
Temperature

Tip: Tweak one variable at a time so you know which variable made the difference.

A perfect cup of cold brew is smooth & refreshing, not bitter. By following these tips you can adjust your brewing process until you find your perfect balance.

If you want to dig a little deeper I have previously written about what I consider the 4 most important variables in cold brewing and how they inter-relate with each other.

Resources consulted when preparing this article:

Roast level and flavors:

Alstrup, J., Petersen, M., Larsen, F. H., & Münchow, M. (2020). The Effect of Roast Development Time Modulations on the Sensory Profile and Chemical Composition of the Coffee Brew as Measured by NMR and DHS-GC–MS. Beverages.

Cai, Y., Xu, Z., Pan, X., Gao, M., Wu, M., Wu, J., & Lao, F. (2022). Comparative Profiling of Hot and Cold Brew Coffee Flavor Using Chromatographic and Sensory Approaches. Foods, 11.

Shi, Q., Xiao, Y., Zhou, Y., Tang, W., Jiang, F., Zhou, X., & Lu, H. (2024). Comparison of Ultra-High-Pressure and Conventional Cold Brew Coffee at Different Roasting Degrees: Physicochemical Characteristics and Volatile and Non-Volatile Components. Foods, 13.

Zhang, D., Gao, M., Cai, Y., Wu, J., & Lao, F. (2024). Profiling flavor characteristics of cold brew coffee with GC-MS, electronic nose and tongue: effect of roasting degrees and freeze-drying. The Journal of the Science of Food and Agriculture.

Coffee to water ratio:

Córdoba, N., Pataquiva, L., Osorio, C., Moreno, F. L., & Ruíz, R. (2019). Effect of grinding, extraction time and type of coffee on the physicochemical and flavour characteristics of cold brew coffee. Scientific Reports, 9.

Nokabun, K. Y., & Handoko, Y. A. (2024). The Effect Of Cold Brew and Hot Brew Extraction Methods And Duration of Fermentation On The Quality Of Robusta Coffee Wine (Coffea canephora) TEMANGGUNG. Agrisaintifika: Jurnal Ilmu-Ilmu Pertanian.

Extraction Time:

Chen, S., Xiao, Y., Tang, W., Jiang, F., Zhu, J., Zhou, Y., & Ye, L. (2023). Evaluation of Physicochemical Characteristics and Sensory Properties of Cold Brew Coffees Prepared Using Ultrahigh Pressure under Different Extraction Conditions. Foods, 12.

Kwok, R., Ting, K. L. W., Schwarz, S., Claassen, L., & Lachenmeier, D. W. (2020). Current Challenges of Cold Brew Coffee—Roasting, Extraction, Flavor Profile, Contamination, and Food Safety. Challenges.

Temperature:

Schwarzmann, E. T., Washington, M. P., & Rao, N. Z. (2022). Physicochemical Analysis of Cold Brew and Hot Brew Peaberry Coffee. Processes.

Dilution

Batali, M. E., Lim, L. X., Liang, J., Yeager, S. E., Thompson, A. N., Han, J., Ristenpart, W., & Guinard, J. (2022). Sensory Analysis of Full Immersion Coffee: Cold Brew Is More Floral, and Less Bitter, Sour, and Rubbery Than Hot Brew. Foods, 11.

Chonpracha, P., Gao, Y., Tuuri, G., & Prinyawiwatkul, W. (2019). Possible Sugar and Calorie Reduction by Visual Cues: A Case of Syrup Added to Brewed Coffee. Journal of Food Science.