Why Does Starbucks Add Water to Cold Brew?

If you ever enter a Starbucks and order a cold brew coffee, you may realize that Starbucks likes to add water to its drinks. Some may never question it as they are there to enjoy the coffee and not the science behind it. However, you may be one who wants to know why they do this. Well, why does Starbucks add water?

Starbucks adds water to its cold brew coffee because they brew it as a concentrate. Adding the water at the end of the process instead of at the beginning allows them to store more cold brew in less space. Customers can request not to have the water added, but it would be extremely strong.

Keep reading to learn more about Starbucks’ cold brews!

Am I getting less for my money?

No. Starbucks customers are not getting less bang for their buck by buying cold brews from Starbucks. Baristas at Starbucks are not watering down the cold brew. Starbucks brews its cold brew differently than most coffee shops do. One customer had the concern that “The local coffee shops don’t water their cold brew down and when I’ve made it at home, I don’t water it down. Every recipe I’ve found online for cold brew doesn’t have a step for diluting it with water.”

Read on to learn more about how Starbucks’ method of making cold brew is different from other coffee shops as well as how their method does not diminish the coffee experience for Starbucks customers.


Most coffee shops will brew their cold brew just as cold brew. However, Starbucks brews it as a concentrate in order to be able to store more of their cold brew in the shops at one time without detracting from how much they can store of their other popular products. Because it is so concentrated, it has extremely high caffeine levels and is too strong for most people to be able to enjoy it. It is the same reason that many people enjoy sweetened milk chocolate as opposed to dark chocolate which is more concentrated (though naturally so). There are some customers who request to have their cold brew served in all its highly concentrated glory, but that’s just too much for the general public.

Concentration Levels

A common, and desirable, ratio of concentrate that many will accept is a cold brew that is either 1:2 or 1:4. This means that the cold brew is either 1 part coffee to 2 parts of water, or 1 part coffee and 4 parts water. This is the sweet spot for most cold brew coffee lovers, but Starbucks has discovered its own method and many customers have fallen in love with it.

When brewing the concentrate Starbucks starts out with a coffee grounds to water ratio of 4:1. After combining the grounds and water together and allowing them to steep, the barista is left with a highly concentrated mixture. When serving it they bring it down from its highly concentrated state by adding water in order to reach a lower concentration level that can be enjoyable for Starbucks customers. Of course, there are some customers who have decided they prefer their cold brew concentrate without the water leveling it out.

A similar situation to Starbucks adding water to their cold brew would be any restaurant adding water to their soda syrups. 4 parts water to 1 part syrup. This is because drinking just the straight-up syrup would be ridiculous due to it being a concentrate. Although restaurants typically won’t let customers ask for a cup of just the soda syrup the way that Starbucks allows customers to request not having the water added to their cold brew concentrate.

Times and temperatures

In cold brew coffee, heat is replaced with time in order to It is recommended to soak the coffee grounds for about 11-18 hours, depending on the desired taste, and at room temperature between 68-72-degree Fahrenheit. Starbucks tends to soak theirs for closer to 20 hours. This is another factor that leads to the undiluted concentrate having such an extreme flavor.

Refrigeration allows the cold brew to retain the flavor effectively and last longer without spoiling compared to when other coffee shops store it at room temperature. This leads to the cold brew lasting only a couple of days before it spoils. Starbucks keeps its cold brew refrigerated in order to have it be able to last longer. Not adding water to the concentrate until it is being served to a customer also helps to increase its shelf life.

Customer satisfaction

The general consensus from customer reviews about Starbucks cold brew is that it is delicious when brewed properly. However, there also seems to be a shared opinion that it is not consistently brewed properly. Starbucks customers have provided several different theories as to why this may now be the case.

Some are of the opinion that the baristas now working at Starbucks do not have the same passion for coffee as baristas of the past. A similar theory is that Starbucks baristas aren’t necessarily all very skilled and thus are more likely to make the mistake of not steeping the cold brew for long enough or adding too much water afterward. Supporters of this theory also suggest that it’s possible these mistakes are made due to cold brew still being a relatively new addition to the Starbucks menu.

One Reddit user said, “the one thing that I have noticed is that Starbucks cold brew tastes very different depending on the location. Some of the tastiest cold brew ever has been from Starbucks. And then sometimes it tastes like they used yesterday’s drip and poured it over ice. Long story short, There’s no consistency with Starbucks cold brew. Possibly because it’s still a “new” product for them and there seems to be a lack of training.”

Despite whatever customers may be writing in their reviews, the fact is that Starbucks’ sales of cold drinks have increased drastically over the years. The revenue from cold drinks has gone to a little over a quarter of their sales from nearly 3 quarters as of 2021.

Charlie McFarlane

Specialty Coffee Enthusiast. Hungry for knowledge in the art and science behind specialty coffee and decided to document my journey, while sharing it with the public. More than 10 baristas were interviewed; over 21 farms were visited across 5 countries. Almost 100 Coffee Shops. Bean of choice: Pacamara. Preferred coffee country: Panama. Preferred Brewing Method: Aeropress. Facebook | Instagram | Twitter

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