Does Weak Coffee Have Less Caffeine?

one latte and one flat white

I want a nice, weak cup of coffee … said no one, ever. The term “weak,” especially pertaining to coffee, connotes a watery, less caffeinated cup of joe. But does weak coffee really contain less caffeine?

Does weak coffee have less caffeine? If you consider that the strength of the coffee is determined by its coffee-to-water ratio, then, yes, weak coffee does contain less caffeine.  When coffee is brewed with a lower coffee-to-water ratio, less caffeine will be present in each cup.

So, what is considered a good coffee-to-water ratio that optimizes both flavour and caffeine level? A general guideline that is actually called the “Golden Ratio” is one to two tablespoons of ground coffee for every 6 ounces of water.

Of course, this ratio can be adjusted to suit your individual taste, but it is suggested not to measure less than this ratio as you may end up with weaker coffee. The ratio will also be dependent on your brewing method and the type of coffee beans used, but starting with this guideline should result in a well-caffeinated cup of coffee.

How Much Caffeine is in a Cup of Coffee?

Scrabble cups with black coffee

The National Coffee Association states that a standard 8-ounce cup of brewed coffee contains an average of 95 milligrams of caffeine. It can be as low as 75 milligrams and as high as 165. Decaffeinated coffee is not immune, containing about 2 milligrams of caffeine per cup.

Many factors can influence caffeine levels, however, so it is somewhat difficult to determine the exact amount in a cup of coffee. Different coffee beans, soil conditions, moisture levels and brewing techniques all play a role in determining caffeine amounts.

How Much Caffeine is Too Much?

If you are a healthy adult, you should be able to tolerate 400 milligrams, or about four to five cups of coffee, a day without any negative or dangerous side effects. Everyone metabolizes caffeine differently, however, and some may be more sensitive to its effects than others. [source]

A sensitivity to or over-consumption of caffeine may cause:

  • Insomnia
  • Restlessness
  • Shakiness/jitters
  • Fast heart rate
  • Upset stomach
  • Nausea
  • Headache
  • Depression

Although it has been looked at in a more negative light, caffeine, a naturally occurring stimulant, may actually provide some substantial health benefits. Caffeine and coffee consumption are being studied as potential benefits to diseases such as cancer, cardiovascular disease, diabetes and stroke. [source]

It seems important, then, to reap all the benefits of caffeine by being able to brew a stronger, more caffeinated cup of coffee.

What Causes Weak Coffee?

There are several factors that create a weak cup of coffee, but below or some of the most important reasons:

  • Not using enough coffee. As stated above, follow the “Golden Ratio” guideline. Using less coffee will result in bland, watery coffee.
  • Not brewing long enough. Just like tea, coffee gets stronger the longer it steeps. Weaker coffee occurs when coffee doesn’t have enough time to interact with the water because its flavour won’t get fully extracted.
  • Brewing at the wrong temperature. Ideal brewing temperature is between 195 and 205 degrees, but if you let the water cool for too long your coffee will end up tasting weak.
  • Coffee grounds are the wrong size. If you grind your own coffee, it is important to have your grounds the proper size for your brewing method. If you are using too coarse of a grind for any method, you will not extract enough flavour and will end up with watery, weak coffee.

What Makes a Good Cup of Coffee?

french press, kettle grinder and coffee

Start with good beans. Great coffee uses great tasting, fresh coffee beans. Purchase whole, fresh-roasted beans in small amounts to guarantee freshness.

When you use pre-ground coffee, you lose flavours from the oils that are inside the whole beans. When oils from pre-ground beans are exposed to the air, they lose moisture, aroma and flavour.

Store your beans properly. Whole-bean coffee should come in vacuum-sealed bags with one-way valves at the top. The valves allow gas to escape but don’t allow oxygen to enter. Once you open the bag, beans should be used within two weeks.

Store beans in an airtight container that is in a dark, cool, dry location. Don’t store them in the refrigerator or freeze, as odours and humidity may damage the integrity of the beans.

Grind your beans well. Make sure to grind beans as close to brew time as possible. Use a burr grinder to get the most consistent grind. The size of the grind is very important to the taste. If your coffee ends up tasting bitter, your grind may be too fine. If your coffee tastes flat or weak, your grind may be too coarse.

Choose the right water. The water used to make a great cup of coffee is very important. For best results, use filtered or bottled water. Never use distilled or softened water.

Water temperature is also important, but most automatic brewers regulate the temperature. If necessary, maintain a water temperature between 195 and 205 degrees Fahrenheit. If the water is colder, the result will be flat tasting coffee. If it is too hot, the coffee will also lose some of its flavour quality.

Follow the “Golden Ratio” rule. This can be adjusted, depending on your machine of choice and how strong you want to make your coffee.

Choose the correct brewing time. Having your ground coffee beans in contact with the water for the proper amount of time is another important factor. Following is a guideline for different applications:

  • Drip-Brewed – around five minutes
  • French Press – two to four minutes
  • Espresso – 25 to 30 seconds
  • Cold Brew – steep overnight (or 12 hours)

You may need to experiment, and if you are not happy with the taste of your coffee, you are either over-extracting (the brew time is too long) or under-extracting (the brew time is too short). Take your time and find the right brew time that works for you.

How to Get More Caffeine in a Cup of Coffee

Brewing coffee in a chemex

If weak coffee contains less caffeine, then it stands to reason that strong coffee contains more caffeine. This is true if you understand what “strong” coffee is when thinking about the notion of caffeine.

The first thing to note about getting more caffeine out of a cup of coffee is what doesn’t work. For example, brewing the same set of coffee grounds twice and making a “double-batch brew” will not give you twice the amount of caffeine.

Caffeine is very water soluble and doesn’t require much time to extract from brewed coffee grounds. Once a single batch of coffee is brewed, it is pretty certain to have pulled all its caffeine.

Three Easy Ways to Get More Caffeine

1. Use More Ground Coffee. By simply increasing the amount of coffee in your coffee-to-water ratio, you will increase the amount of caffeine. As an example, if two tablespoons of ground coffee will give you “x” amount of caffeine, then four tablespoons will give you twice as much.

Just note that if you increase your amount of coffee just to get a stronger, more concentrated (and caffeinated) cup of coffee, you may end up with a bitter, overly-strong tasting brew.

2. Drink a Stronger, Quicker Brew. If you want caffeine to give you an immediate lift, then you need to look at the quantity of caffeine consumed over time. Drinking an espresso as compared to brewed coffee will give you a quick boost to your day.

Although an 8-ounce cup of coffee may contain around 100 milligrams of caffeine and a 1-ounce cup of espresso contains 45 milligrams, you will take much longer to drink that cup of coffee. Drinking an espresso shot takes about 10 seconds, allowing your body to process the caffeine much quicker.

3. Use Coffee Beans that Contain More Caffeine. Although it’s minimal, light roast coffee is known to contain more caffeine than dark roast. When beans are roasted longer, they lose more water and become less dense. If you measure by volume, lighter roast coffee will have more beans, and more beans mean more caffeine. However, if you measure your beans by weight, there is no difference in caffeine level.

If you genuinely want a higher quantity of caffeine in a single cup of coffee, then you need to get Robusta coffee. The typical Robusta bean has about twice as much caffeine content as the more commonly used Arabica bean. Some beans may reach as much as four times the caffeine.

With Robusta beans, your choosing quantity over quality. The downfall to the Robusta bean is, because of the high caffeine content, it tends to brew a very bitter cup of coffee.

The Difference Between Weak Coffee and Strong Coffee

At the beginning of this post, it was stated that weak coffee contains less caffeine. This leads one to believe that stronger coffee contains more caffeine. But what is weak coffee and what is meant by strong coffee?

The bottom line is that it comes down to perception and preference. Just as people have certain preferences for red or white wine or bold IPAs versus light and fruity lagers, they also may prefer a weaker coffee brew over a stronger one.

Also, some people may have the perception that weak coffee is bland coffee or that strong coffee is bitter coffee.

What constitutes weak coffee?

  • Less caffeine
  • Less bitterness
  • A lighter roast
  • A cleaner, brighter flavor
  • Waterier look and feel

The idea of strong coffee is more universally accepted and appealing. More often, you hear people asking for a good, strong cup of black coffee than anything else. Moreover, coffee companies will promote their product using the term to describe how good their coffee tastes. However, again, what is the true definition of “strong” when it comes to coffee?

What constitutes strong coffee?

  • More caffeine
  • More depth
  • A heavier, bolder flavor
  • More intensity
  • A darker look

Coffee, just like many things, is a matter of taste. And, although most people perceive a strong cup of coffee as a preferred cup of coffee, we shouldn’t get caught up in the connotation behind a weak cup of coffee.

Never mind – I still stand by my statement that no one has ever asked for a nice, weak cup of coffee and most likely no one ever will!

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