A Complete Guide to Coffee Acidity: What Causes It and How to Make Coffee Less Acidic

For so many coffee drinkers, the daily ritual of coffee involves scooping pre-ground beans into a cheap drip coffee maker and brewing a quick cup. But this convenience often comes at the cost of flavor. Drip machines and big companies that sell pre-ground coffee often lead to too much coffee acidity, making the taste of black coffee without additives like milk and sugar unpleasant. If you want to enjoy flavorful coffee at home without an overly acidic flavor, it’s important to understand what causes coffee acidity and how you can minimize it.

In this comprehensive guide, I’ll explain the science behind coffee acidity and outline techniques you can use right at home to brew a flavorful, aromatic cup with significantly reduced acidity and a more balanced flavor.

The Basics of Coffee Acidity

The average pH of coffee falls between 4.5 and 5.5 on the pH scale, which makes it quite acidic compared to water (pH of around 7). In fact, all coffee is inherently acidic to some degree. This acidity comes from natural organic acids present in the coffee cherries, like citric acid, malic acid, chlorogenic acid, acetic acid, and quinic acid.

When balanced properly with coffee’s natural bitterness and sweetness, acidity can actually be a positive quality—it adds brightness and fruitiness to the cup. A coffee with no acidity would taste flat and hollow.

The key is balance; acidity should complement the other flavors rather than overwhelm them. However, one of the most common complaints about coffee is that it’s too acidic or sour tasting. So…how do you fix overly acidic coffee? First, you need to understand why coffee is acidic in the first place.

What Makes Coffee Acidic?

The sensation of acidity in coffee is complex. It doesn’t correlate directly with a coffee’s measured pH value but rather depends on perceived acidity. Perceived acidity is influenced by the concentrations of organic acids, the roast level, the grind size, and the brewing parameters. Many factors come into play.

All coffee contains organic acids like citric, malic, acetic and phosphoric acids. The types and amounts vary by coffee origin and processing method. For example, coffees processed by the natural or honey methods often have higher acidity since the beans dry while still surrounded by fruit flesh, allowing fruit sugars to seep into the seeds. The sugars break down into various acids during roasting.

Despite the universal presence of these acids, they don’t always translate to noticeable acidity in the cup, and certainly not to overly acidic coffee. That’s because acidity has as much to do with balance as concentration. Bitterness and sweetness balance out bright acids. If a coffee tastes too acidic, it usually means it is under-extracted and hasn’t developed enough of those other balancing flavors.

Let’s look at the major factors that contribute to under-extraction and acidic coffee.

Type of Coffee Beans

The two main commercially grown coffee species are Arabica (Coffea arabica) and Robusta (Coffea canephora). Arabica is considered higher quality; it has about half the caffeine of Robusta (the strongest coffee variety in terms of caffeine) and is described as having sweeter, more complex flavors. Robusta is harsher, more bitter, and often contains higher amounts of chlorogenic acids.

Since Robusta is more bitter, it can mute the perception of acidity by overwhelming the palate. Arabica is a better canvas for subtle acids to shine, but with less bitterness, Arabica coffee can easily become too acidic.

Within Arabica, there is variation in acidity levels between origins and varietals. For example, varieties like Typica coffee and Bourbon coffee are known for their complex fruit notes, while Catuaí and Caturra tend to be cleaner-tasting.

I still recommend Arabica coffee, but choosing a naturally sweet coffee like Typica can make a noticeable difference in your cup.

Where Your Beans Come From

Coffee flavor is greatly affected by terroir—the soil, climate, altitude, and agricultural practices of the region in which it’s grown. These conditions influence the development of acids and other chemical components in the cherries.

The growing conditions, harvesting practices, and processing methods all make a difference in your final product.

Coffee Growing Conditions

A coffee’s terroir encompasses many elements that affect acidity levels. These include the following:

Soil composition: The mineral content of the soil affects the availability of nutrients for the plant. For example, potassium helps reduce bitterness and enhance sweetness. Nitrogen promotes growth of the plant and fruit. Too much nitrogen can lead to elevated acidity.
Altitude: Higher elevations come with colder air, which slows ripening and leads to a more concentrated accumulation of sugars in the cherry. These sugars convert to acids during roasting.
Shade vs sun: More shade slows down ripening and leads to higher acidity, while more sun accelerates ripening and reduces acidity. Many specialty growers provide moderate shade to balance flavor components.
Rainfall: Too much rainfall can waterlog the soil and promote faster growing, higher yielding coffee, but it usually has lower quality and a higher chance of defects. Ideal rainfall depends on the variety and soil type. Good drainage is key.
Age of trees: Younger trees produce higher acidity coffee than older trees. The reason is unclear, but there is most definitely a correlation between the age of a coffee tree and the acidity you get from the beans.

In terms of optimizing flavor balance, farms located between 2,000 and 4,000 ft in elevation with moderate shade coverage, loam soil, and experienced management often produce stellar coffees with a lower acidity level. Of course, a knowledgeable roaster also needs to complement these beans with the right roast profile.

Coffee Harvesting Method

Coffee cherries don’t all ripen at the same time, and the acidity level depends, in part, on the harvesting method.

Hand-picking ensures only perfectly ripe cherries are selected, while mechanical harvesting scoops up everything. If underripe cherries make it into production, it can lead to elevated acidity; they haven’t developed the sugars needed to balance acidity.

This effect is compounded if the coffee is then processed by the washed method, since the beans are soaked to remove fruit flesh. The beans themselves will have fewer sugars inside of them, so the acidity shines through more readily. Carefully hand-picked and dry-processed coffees are a good bet for smooth flavor.

Coffee Processing Method

After harvest, the first step is drying out the beans. There are a few ways coffee farmers can accomplish this, each of which plays a role in how much acidity you’ll experience in your coffee.

Dry/Natural: The whole cherries are dried in the sun on patios for several weeks before the dried fruit flesh is mechanically scrubbed off. The beans never come in contact with water. This leads to lower acidity since the fruit acts as a barrier to sugar penetration.
Washed: The fruit flesh is removed within hours of picking, then the beans are steeped in fermentation tanks. This allows the sugars to interact directly with the beans, often resulting in brighter acidity.
Honey: The cherries are de-pulped, then laid out to dry for a few days with some sticky fruit residue still attached before drying completes. Acidity levels fall between dry and washed methods.

Generally, natural and honey processed coffees will be less acidic. But optimal acidity depends on matching processing style to the intrinsic qualities of the bean. A drier bean will benefit from washed processing to liven it up, while a wetter bean benefits from the muting effects of natural drying.

Roast Profile

Roasting doesn’t create acids, but it changes their solubility. In the early stages of roasting, chlorogenic acids are transformed into quinic and caffeic acids that contribute to a coffee’s acidity.

As the roast progresses, these acids and other flavor components break down. Lighter roasts retain more acids while darker roasts exhibit mellower acidity, and more of a bitter, smoky quality. The exception to this would be quinic acid. As coffee beans are roasted darker and reach higher internal temperatures, the chlorogenic acid breaks down into quinic acid and caffeic acid. As such, dark roasts have higher levels of both quinic and caffeic acids. However, these taste less astringent than chlorogenic acid and have less of an impact on perceived acidity in your coffee.

Full City to French roasts reduce many of the fruit notes that make acidity taste bright and pleasant. As the roast darkens, you’ll generally lose acidity and move toward bitterness. Of course, finding a sweet spot is best so that you don’t end up with overly acidic or bitter coffee.

Grind Size

The grind size you choose greatly affects extraction, and, in turn, the acidity. With all other brewing parameters remaining constant, grinding finer will speed up extraction, reducing perceived acidity, while grinding coarser will slow down extraction, increasing perceived acidity.

The only exception to this rule is with espresso, especially if your grinder doesn’t create a consistent grind size. Grinding finer for espresso means more resistance, and since water takes the path of least resistance, any grounds in your coffee puck that are a little coarser will give way to the water. The water will travel through channels in your puck rather than soaking through the entire thing, which means underextraction and increased acidity.

Brewing Method

The various coffee brewing methods have different effects on acidity. Drip machines are notorious for underextracted, acidic coffee due to less control over parameters like temperature, agitation and brew time. Quality machines help because they reach proper brewing temperature. Cheaper machines tend to brew at lower temperatures, which leads to a slowed rate of extraction and an acidic flavor.

Pour over can highlight acidity because the grounds aren’t immersed in hot water, so they extract less than they would if they experienced consistent contact with the water. Focus on nailing the right grind size, ratio, and pour pattern to brew lower-acidity pour over coffee.

Cold brew mutes acids because grounds steep in room temperature water for hours. The long brew time and low temperature extracts more sweetness to balance acidity.

Espresso under-extraction yields acidic, sour shots. Sour flavors come from uneven extraction caused by faults like channeling. The water temperature, grind size, puck preparation methods, and pressure can all contribute to making acidic espresso.

Ideally, whichever method you use should fully saturate all the grounds to extract sweeter components along with acids, and it should always use the proper water temperature for a good rate of extraction. Cold brew is foolproof, but it also mutes origin character a bit in favor of darker tasting notes and sweetness.

Dose/Brewing Ratios

The dose of coffee (mass of dry grounds) in proportion to brewing water greatly affects extraction efficiency. If you don’t use enough coffee, you’ll highlight the acids in the grounds rather than getting the full flavor.

Below are some common standards:

Drip machine: 1 Tbsp ground coffee per 6 oz water
Pour over: 1g coffee per 15 to 17g water
French press: 1g coffee per 15 to 17g water
Espresso: 7-9g coffee per 25 to 30g brewed shot

If your current dose is leading to weak, acidic coffee, try adding more grounds while keeping water volume and all other parameters.

Water Quality

Water accounts for about 98% of brewed coffee, so its qualities significantly influence acidity and the overall taste. Hard water is high in minerals like calcium and magnesium. These minerals bind with flavor components and prevent their extraction, resulting in weaker, acidic coffee.

Soft water allows your coffee’s natural acids to extract cleanly, making their flavor more noticeable. But too soft is also undesirable, since you need some mineral content to activate the flavor potential of the grounds.

Ideally you want moderately soft water—about 50 to 150 ppm total dissolved solids. You can use filters to remove excess minerals if your tap water is too hard. Third wave coffee shops often use reverse osmosis filtration and remineralization to create an optimal brewing water profile. You can instead use bottled water if you can’t get your tap water within the desired hardness range.

Brew Time

Acidity forms during the very early phase of extraction, while sweetness and other balancing notes like flavors from bitter compounds take longer to draw out. If your brew time is drastically short, you’re probably only extracting acids, causing an unbalanced, sour brew.

Aim for the following brew times based on your brewing method:

Drip machines: 4 to 6 minutes
Pour over: about 4 minutes
French press: about 4 minutes steady steeping before pressing
Cold brew: 12 to 24 hours at room temperature

If your current brew time for hot coffee is just 1 to 2 minutes, which you might get with a low-end drip machine or single-serve coffee maker, try grinding finer to increase resistance for a slower extraction. For immersion brewing like French Press, let it steep longer before plunging the filter.

Water Temperature

Hotter water extracts compounds from your coffee grounds more quickly. Too low of a brew temperature can lead to under-extraction and unbalanced acidity. If you have the ability to dial in your water temperature for brewing, aim for the following:

Drip machines: 195 to 205 degrees (F)
Pour over: 200 to 205 degrees (F)
French Press: 200 to 205 degrees (F)
Espresso: 196 to 204 degrees (F)

Lower temperature is a bit better for dark roasts since heat diminishes aromatic oils. But for light or medium roasts, optimal extraction of acids and other components occurs at around 200 degrees (F).

How Fresh Your Coffee Is

Freshness greatly affects quality, including acidity levels. Coffee begins to stale about two weeks after roasting and immediately after grinding. For whole beans, optimal freshness lasts only about two weeks. Pre-ground coffee goes stale within minutes.

Why? As soon as the beans are cracked open during grinding, oxidization and loss of carbon dioxide occur rapidly. The escaping gasses are what give coffee its aromatics and fresh flavors. Ground coffee on supermarket shelves is almost guaranteed to be flavorless and acidic.

For the freshest, non-acidic coffee, buy small batches of whole beans from specialty roasters and grind right before brewing. Keep the whole beans in an airtight container away from light, air, moisture, and heat to preserve freshness.

How to Fix Acidic Coffee

While coffee will always naturally be acidic because of the acids found in all coffee beans, there are a few ways to reduce the astringency if it becomes an overwhelming flavor in your cup.

Add Milk or Milk and Sugar

Solution: Spruce up your coffee with additives

Adding a splash of milk or milk and sugar to your coffee can help reduce the perception of acidity. The proteins in milk help neutralize acids while the sugar masks any harsh sourness. This is not a perfect solution, as it dilutes the coffee’s natural flavor. But it’s an easy fix if you’ve already brewed a pot that’s too acidic to drink black. The dairy and sweetness complement the existing flavors to make it more palatable.

Use a Higher Coffee-to-Water Ratio

Solution: Brew with more coffee grounds

Increasing the amount of coffee grounds relative to water when brewing can help reduce acidity. This raises the extraction yield, meaning you pull out more dissolved solids. More coffee solids balance against the acids for better flavor. For drip machines, use 2 tablespoons of grounds per 6 oz of water instead of just 1. For pour over, increase the grounds to at least 1g per 15g of water. The higher concentration of grounds extracts more sweetness and bitterness to counter the acids.

Choose a Medium or Dark Roast Coffee

Solution: Go for a darker roast

Opting for a medium or dark coffee roast is an effective way to tame down acidity. Lighter roasts retain more organic acids that make their way into your brewed coffee. As roasting progresses, chlorogenic acids transform into bitter compounds while sugars caramelize. The darker the roast, the lower the acidity.

Full city roasts have a more well-rounded flavor with muted acidity, but take care not to go so dark that origin character disappears. Aim for a full city roast if acidity is an ongoing issue.

Grind Finer for Immersion Brewing

Solution: Finer grind = lower acidity

If using a French press or other immersion method, try grinding your coffee a bit finer. This will speed up the rate of extraction, so even with the same brew time, you’ll get more compounds out of your grounds to balance the acidity that extracts early on. A medium-coarse grind exposes more surface area to the hot water for thorough extraction of acids as well as balancing flavors. The result is a smoother, mellower tasting cup.

Change Up Your Brewing Method

Solution: Try cold brew

Cold brewing is one of the most foolproof ways to tame coffee acidity. The grounds steep for hours at cool room temperature rather than hot. This long, gentle process naturally reduces acidity and yields sweeter flavor notes. While hot brewing highlights brightness, cold brew mutes acids. Try this method if traditional hot brewing always yields coffee that is too tart for your tastebuds.

Increase Brew Time for Hot Coffee

Solution: Longer brew = lower acidity

For drip, pour over, and French press, allow a longer brew time to fully extract sweetness and bitterness along with acids. Acidity extracts early while other flavors need more time. Lengthening the brew time to 4 to 5 minutes can help achieve balanced extraction. For pour over, a slower pour rate also helps lengthen brew time and reduce harsh acids.

Tips for Highlighting Pleasant Acidity

Mild acidity can be quite enjoyable if it’s properly balanced. When you also get natural sweetness and balancing bitterness in your cup, you might start chasing after that coffee acidity for more nuanced and complex flavor profiles. To enhance bright flavors and pleasant acidity in your coffee, use the following tips:

Choose a washed Ethiopian or Kenyan coffee known for pleasant fruit notes.
Use a pour over method for clean acidity extraction.
Go with a light roast to preserve acids and aromatics.
Grind a little coarser than usual to promote acidity.
Use the freshest beans possible and grind right before brewing.
Brew with slightly lower water temperature, but don’t go lower than 195 degrees (F).
Limit the brew time so that you don’t get too much bitterness.
Choose a coffee origin that’s known for bright acidity. African coffees tend to have a delightful acidity and fruitiness.

Health Implications of Acidic Coffee

Some people perceive coffee as aggravating digestive issues. However, studies indicate that coffee stimulates gastric acid secretion only modestly and temporarily. For healthy individuals, coffee’s acidity is not a major concern. However, those with chronic heartburn or GERD may want to limit intake.

On the other end of the spectrum, coffee, despite acidity, can be quite beneficial. Coffee beans contain phytonutrients and antioxidants that actually may reduce the risk of gastrointestinal cancers.

With all of that being said, studies on coffee’s health effects often lack control for other lifestyle factors. Talk to your doctor about whether reducing dietary acids from coffee and other sources may be beneficial in your individual case.

Wrapping Up: How to Brew Less Acidic Coffee

Acidity is an integral part of coffee’s flavor makeup, but excessive acidity is unpleasant. Through careful coffee selection and proper brewing, you can achieve a harmonious balance of sweetness, acidity, bitterness, and aroma for a smooth tasting cup.

Pay attention to all the variables—coffee origin, roast level, grind size, water quality, brew time, and temperature to optimize and balance the acidity in your coffee. With some tweaking of parameters and a quality coffee batch, you’ll be sipping a perfectly balanced cup in no time.

And if you go too far in the other direction, use my guide on reducing coffee bitterness!

Frequently Asked Questions

Why does my coffee sometimes taste very sour and acidic?

The acidity in coffee can get out of balance due to under-extraction of the grounds during brewing. Acidity is extracted early in the brewing process, while sweetness, bitterness, and other flavors require more time and contact with water to draw out. Brewing with overly coarse grounds, low water temperature, or a very short brew time can lead to a coffee high in acids but lacking in sweetness and bitterness to balance it out.

Is light or dark roast coffee less acidic?

Darker roasts are less acidic. As coffee beans roast longer at higher temperatures, their natural acids break down more. Light roasts retain more brightness and fruit notes from acids. But take dark roasting too far and you risk burning the beans, removing positive flavor notes, and increasing bitterness. A medium or medium-dark roast strikes a good balance between preserving acidity but still keeping it under control.

What is the best way to reduce bitterness and acidity in cold brew?

Bitterness and acidity can be minimized in cold brew through proper coffee grind size and coffee-to-water ratio. Use a coarse grind to allow water to permeate the grounds and extract fully without overextracting. Finer grinds lead to over-extraction of negative flavors. A brew ratio of around 1:4 to 1:8 coffee to water is ideal for smooth cold brew. Steep the grounds for 12 at room temperature or 24 hours in the fridge. The slow cold water extraction naturally reduces acidity and bitterness.

Can I make my coffee less acidic by adding baking soda?

Adding a small pinch of baking soda can temporarily reduce acidity in brewed coffee by raising the pH. However, this also imparts a soapy flavor and sodium. It’s best to use proper brewing techniques to extract a balanced cup with a lower perceived acidity instead of altering the coffee’s pH after brewing. Proper grind size, water quality, brew time, and brew temperature all help minimize acidity through optimized extraction.