Introductions
The debate over how to enjoy chilled coffee the best is timeless. Cold Brew VS. Iced Coffee will always be a topic of discussion for those who like drinking their coffee cold, mainly due to the fact that the preference for either has become widely polarized.
Of course, there is more to our preferences than just a brewing method, but before we delve into differences between extraction theories, we must ask ourselves why we prefer one over the other. Do we like the acidity level? The texture and mouthfeel? Or do we simply enjoy the convenience of one over the other?
There are multiple reasons why you would prefer one brewing method over the other; however, in this discussion we will dig into the objective facts surrounding each brewing style, and a bit into some theories as well.
Stick with us here as we get to the bottom of this debate. By the end, at the very least, we can help you defend your choice and ultimate preference of your chilled coffee beverage — and hopefully learn something along the way.
What Is Iced Coffee?
Iced coffee, or “flash brew”, also referred to as Japanese-style iced coffee, is the process of brewing cold coffee using a drip filtration method. Hot water pours over the coffee grounds and runs through a filter that lands directly over ice to flash chill. Once it’s completed brewing, it’s ready to serve over ice.
What Is Cold Brew?
Cold brew is the process of submerging and steeping ground coffee in cold water, then letting it extract in a container anywhere from 12–24 hours, then eventually filtering out the coffee grounds and preparing it for service. Most cold brew is served over ice, other than Nitro Cold brew. Nitro Cold brew is just an added step where the coffee is infused with nitrogen to influence the texture; hence, why it is not served over ice.
These are definitions of each beverage based on brewing style, but the method to brew either iced coffee or cold brew has a definitive impact on the final taste in the cup. This is due to the category or brewing they fall into. When we really begin to dissect the differences between the two, we have to start at the very beginning.
Factual Generalizations
The reality of this situation we have found ourselves in, from the most objective and general viewpoint, depends on whether you prefer the filter coffee or full immersion brewing method.
These are the two main styles of brewing that exist, and it just so happens that iced coffee and cold brew fall on opposite ends of the spectrum. Let’s talk about the main differences between the two.
Filter coffee is the brewing process of putting ground coffee in a filter, letting water run through that coffee and the filter, then collecting the brewed coffee in a separate vessel. Iced coffee, or flash-brew coffee, falls under this category.
Full immersion is the brewing process of putting ground coffee and water in the same vessel and allowing the slurry to rest together, or “steep”, like a French press. Cold brew coffee falls under this category.
While each brewing method requires different steps, the most important difference between the two main styles of brewing will always be taste.
Filter coffee is able to trap ultrafine coffee solids and oils in the filter and prevent them from ending up in your final cup. This assists filter coffee — iced coffee included — in having a more acidic and cleaner cup quality. We are able to taste the sweetness and complexity of the coffee better. We can distinctly taste each tasting note of the coffee, due to that filter holding back those tiny coffee particles and oils. As a result we can see an increased amount of separation of flavor and complexity, regardless of which coffee we brew.
Whereas full immersion brewing methods — like cold brew — are more likely to have a bigger texture and mouthfeel. Coffee solids end up making their way into the final cup because of prolonged contact between the coffee grounds and water; and sometimes due to the lack of presence of a filter. These coffee solids and oils present in full immersion brews prevent most final cups from having immense clarity. Most cups will be consistent, however lacking the complexity. Most of the time we would describe full immersion cups as ‘muddy’ or lacking that separation of flavor.
This poses a major division for coffee drinkers — purely based on taste.
Those who enjoy and love cold brew tend to appreciate a less complex, smooth coffee that pairs well with milk due to the bolder texture and mouthfeel.
Whereas iced coffee drinkers tend to enjoy a refreshing, fruity coffee with bright acidity and complexity, most likely opting to drink this style of coffee on its own without any added milk or sweetener.
Just based on the styles of brewing — iced coffee falling under the category of filter coffee and cold brew falling under full immersion — we see a massive division based on how each coffee tastes. While it sounds like each of these brewing methods are fairly comparable, I would argue that it actually makes it harder to compare the two purely based on the brewing variables associated with each method.
BREWING VARIABLES
Filter/Iced Coffee
When brewing filter coffee — filtered iced coffee in particular — there are several concepts we must consider before we start brewing.
We must pay attention to the specific grind size, the brewing ratio of coffee to water (including ice), the water temperature, brewing time, agitation style, and more.
It can be incredibly difficult to balance these variables, and learn how they all impact one another. For instance, one of the most tricky parts about the recipe can be finding the correct grind size. With filter coffees, determining a good grind size can be difficult. With most filter coffees, grind size also determines how much contact time there is between coffee and water. Simply put, with filter coffee, the ground coffee is resistant to the water traveling through it. Depending on how coarse or fine you grind your coffee will determine how long the water is in contact with the coffee in the filter.
I like to compare it to rocks and sand, and if you were to pour some water over rocks and the same amount of water over sand, the water would travel through the rocks easier than it would the sand. The grind size of your coffee works the same way, and it will heavily impact the duration of the brew.
All of these different brewing variables must work together in tandem in order to achieve an enjoyable iced coffee. It can be difficult to balance these variables while using the correct brewing techniques. Learning how to brew iced coffee properly takes time and practice. While it is very possible to have outstanding, consistent cups, it might be a bit more difficult to achieve.
However, the brewing style and range of variables of filter coffee does create more opportunity for nuance in each cup. Especially when we are required to hand brew by the cup and are able to control all the variables manually, in the instance of a pour-over iced coffee (i.e., Hario V60, Chemex, Kalita Wave).
In a truly unbiased fashion, I must admit that the price of having many variables is steep. While filter coffee does have the aptitude for creating exceptional cups, as seen widely across specialty coffee for years, the inverse is also true — if even one of your brewing variables is askew, your entire cup is most likely thrown off. Filter coffee, in general, is very volatile — iced coffee included.
Overall, iced coffee has the capability of creating new experiences the drinker might not expect, though the ceiling is raised much higher for nuance and overall quality of flavor profile — no matter which coffee you are drinking — more on this later. With that being said, this does mean that filter brewing is a widely volatile and a delicate process compared to full immersion brewing methods like cold brew.
Cold Brew
With cold brew, there is a stark difference when we begin to compare the sheer amount of brewing variables and, thus, the amount of nuance and complexity we can achieve in each cup.
Cold brew, along with most full immersion brewing methods, has two main brewing variables we must pay attention to and balance: grind size and time.
The recommended grind size across the board for brewing cold brew will likely be pretty coarse. Like any brewing method, the grind size of your coffee grounds will have a big impact on extraction and, as a result, how your coffee tastes.
The coarser grind setting is mainly a result of our other variables, like the water temperature and brewing time. Since we are using cold water, we will need a longer steep in order to properly extract our coffee. The coarser grind helps balance our brewing recipe and extraction — it assists in not over-extracting the coffee considering the elongated brewing time.
With cold brew it is much easier to find a pleasant grind size for each slightly unique recipe. This is something unique about full immersion brewing — and cold brew in particular — is that we (the barista and the brewer) determine the contact time. When we think the coffee is done brewing — or when our timer goes off — we then separate the grounds from the water-turned-cold brew, determining the contact time ourselves instead of the grind size doing so, like in filter coffee (and iced coffee).
With cold brew, these two variables — grind size and time — tend to work mostly independently from one another, thus making it easier to create a well-balanced recipe for this style of brewing. It is easy for the brewer to decide to make a change in the recipe without worrying about the ramifications and the effect it may have on the other variables — we just worry about taste! This is incredibly convenient.
Full immersion brewing tends to result in consistent cups, but cups that are hard to find any clarity or complexity in (though this is not impossible, it also depends on which coffee you choose).
ACHIEVABILITY / ACCESSIBILITY
Baristas vs. Home Brewers
The brewing variables involved in each method have particular relevance if you enjoy making and drinking most of your coffee at home. With only two variables that have relatively simple troubleshooting, you may find that it is much simpler to perfect a cold brew recipe at home. Combined with the more subdued, less complex flavor of cold brew, most home brewers find relative ease of brewing, resulting in increased enjoyment from homemade cold brew coffee.
Whereas iced coffee requires more tools, information, and technique — the difficulty of dialing in and perfecting all the variables makes iced coffee a bit more treacherous. While the payoff is worth it for a sweet, acidic, complex cup, it still might not be feasible for the average coffee drinker to achieve every morning in their kitchen.
Personal Expectations
Regardless of achievability for home brewers, in a cafe experience, I would personally expect the iced coffee to be more complex, and I would hold it to a higher standard than that of its counterpart — cold brew.
This is mainly due to the resources that a cafe has in making their iced coffee the best possible product that they can serve — due to the brewing variables and ability to achieve nuance with iced coffee — as stated above.
This is also a big reason why here at DOCR we only serve iced coffee — more on this later.
Accessibility
I would argue that accessibility makes a bigger difference than any of us imagine in our preferences. It is hard to say that iced coffee is superior to cold brew because it just might not be for a particular person — whether it be due to resources, tools, education, or time.
Ease of access and relative ease of creating recipes makes cold brew into something familiar to many individuals. It’s an option for a cold coffee beverage they can reach for while having their set expectations met because of the consistency in flavor profile.
Accessibility does play a huge role in determining our preferences for brewing methods, but an underlying contributor to a preference between iced coffee and cold brew has to be roast profile, and the types of coffees associated with each brewing method.
ROAST PROFILES
Another factor we must decipher is the type of coffee we’re brewing. As previously mentioned, the brewing methods alone have a big impact on flavor and quality, with cold brew having a bigger texture and mouthfeel while iced coffee has a bit more clarity and brightness.
As a result, we see that certain coffees and roast profiles are commonly correlated with each brewing method — this can play a role in why we prefer one method over the other.
For cold brew coffees, due to the brewing method having a bit less complexity with a bolder texture, we see that most coffees used tend to scale more on the medium-to-dark side of the roasting spectrum. Typically, these coffees complement the brewing method nicely and will give customers something close to what they are imagining when ordering a cold brew.
Whereas with iced coffee, it's more common to see folks brewing with light-to-medium roasted coffees. The flash brew style tends to highlight the complexity of acids, as well as sweetness, and the overall balance of the cup, making light roasts the ideal choice for brewing iced coffee, due to their increased acidity.
If you prefer one method over the other, I think it would be wise to ask why that is and maybe take more factors into account than just the brew method. Maybe you are not sold on the method so much as the type of coffee typically used.
Learn about DOCR's roasting theory, practices and more on roasting techniques in our blog, The Heart of the Roast.
ACIDITY
Another main reason individuals may prefer cold brew over iced coffee is that cold brew supposedly has less acidity. Mainly when people say this, it sounds as if they are saying that the brewing method of cold brew will result in decreased acidity. While I’m not a scientist, I will simply tell you the facts and what I know as a coffee educator and barista of almost 7 years. Please, prepare to go on a wild tangent with me.
My research on soluble acids and the pH of coffee (in particular, the acidity levels in iced coffee versus cold brew) has led me in many different directions. It seems as if no paper, article, or website can agree on much of anything — admittedly making the research aspect of this section challenging. Nonetheless, I’ve decided to include my own thoughts on acids in this timeless debate of Cold Brew VS. Iced Coffee, alongside some research I’ve stumbled upon.
Originally, my research started just casually poking around to see what I could find about acidity. It does seem to be quite the hot topic when comparing iced coffee and cold brew.
It all begins with one article, titled Why Does Cold Brew Taste Different?, that piqued my interest from Barista Hustle. In this article, Barista Hustle explains the importance of comparing pH and TA (Tritable Acidity) when we talk about acidity in coffee. Essentially, we’re talking about acidity vs. perceived acidity. Barista Hustle goes on to reference articles that also grabbed my attention, by NZ Rao and M Fuller, which helped bring me to my conclusion below.
My conclusion: Cold brew — the brewing method — is not actually less acidic than iced coffee. It was hard to find concrete evidence in my findings that it is, in fact, less acidic, even though many posts and articles will claim that it is. I believe cold brew just tastes less acidic than iced coffee, if anything.
I can explain why and how I came to this conclusion if you wish to follow along below:
To begin, when we start talking about acidity in coffee, the most general way to refer to it would be pH. The use of pH is especially relevant in the winemaking community, and some research can be directly applied to acidity in coffee.
One article, titled pH, TA, and Acid Adjustments, from Winemakers Research Exchange explains, “When we measure pH, we are measuring the strength of the acid (or acids) in a solution.” The authors, Beth Chang and Joy Ting, describe how pH is applied to winemaking — a similar effect can be seen in coffee, as it is a solution. The pH of coffee is a measurement of the strength of the acid(s) in the final brewed coffee.
As for pH in coffee, the research referenced in Barista Hustle’s article, Acidity and Antioxidant Activity of Cold Brew Coffee, “found the pH measurements for all coffee samples tested to be comparable, ranging between 4.85 to 5.13. Varying the temperature of the extraction water did not result in distinguishable pH values between hot and cold brew coffees.” Based on this study done by Rao and Fuller, the coffees’ pH — or acidity strength — regardless of what type of acidity, is around the same for both cold brew and hot coffees.
This information seemed very interesting to me. I started to wonder how pH remained very similar for both cold brew and iced coffee brews of the same coffee. I found out more about TA, or titratable acidity.
Coffee’s pH does not tell the entire story. The titratable acidity, or TA, as I will continue to refer to it as — which is popular in winemaking — will tell us the concentration of acids found.
In fact, Rao and Fuller indicated that acids were found to be in higher concentrations across hot brewed coffees and explained that the higher TA in hot brewed coffees...
indicat[es] higher concentrations of extracted acids and/or additional acidic compounds not found in the cold brew coffee extracts.”
The TA of a substance will give us more of a correlation for perceived acidity. The higher the TA, the more likely we are to perceive acidity.
So, how is it that while pH is similar across both hot/cold brews, the TA is higher in hot brewed coffee? I started to research TA and how it is applicable to beverage science.
In their winemaking article, Chang and Ting go on to describe:
As I continued looking into the difference between pH and TA, I found this information fascinating. If TA is a more predictive measurement for perceived acidity, then this would make sense that iced coffee is more acidic than cold brew.
To recap, the TA, or concentration of acids, is higher for hot coffees. However, both iced coffee and cold brew have around the same pH, or acid strength.
As I was thinking about this information and the difference between TA and pH in hot/cold brew coffees, I started to think about the science of acidity in coffee brewing.
Coffee professionals also use acidity to gauge extraction levels for a particular brew. In fact, no matter what coffee is being brewed, acids are always the first compounds to be extracted into the cup. We see this very definitively every time a coffee is brewed.
With this knowledge, the conclusion that cold brew coffee is “lower in acid” simply does not make a lot of sense — especially considering that cold brew is extracted and steeped from anywhere between 12 to 24 hours.
It poses the question: Exactly how would the acids not wind up in the final brew?
Baristas will tell you this is due to temperature, and the cold temperature of the water used for cold brew coffee. Water temperature will affect which acids can break down at that temperature.
However, my research found that most acids are readily soluble in water, even at a cooler temperature, though they might extract just a tad slower. Again, cold brew has plenty of time for the acids to wind up in the final cup — 12 to 24 hours to be exact.
I found that a specific type of acid, chlorogenic acids — or CGAs — will break down into other acids — quinic and caffeic acids, to be specific — at high temperatures. Cold water is unable to break down CGAs into other acids.
My personal theory, and stick with me here, is that hot water allows these larger acid molecules to break down into smaller ones, which will increase the concentration of acids (TA) while minimally affecting the pH, or strength of the final acidity in the cup.
With more research, I found that, “Chlorogenic acids (CGA) are abundant phenolic compounds in coffee, with caffeoylquinic (CQA), feruloylquinic (FQA), and dicaffeoylquinic (diCQA) acids being the major subclasses.” (Titled Chlorogenic Acid Compounds from Coffee Are Differentially Absorbed and Metabolized in Humans, authored by multiple contributors.)
Again, CGA and other acids are water-soluble, even in different temperatures of water, and the increased brewing time for cold brew should allow all of these acids out, due to the fact that they are always first to extract from the coffee. The difference is purely that they can break down when extracted with hot water, unlike with cold water.
In another article by Rao and Fuller, Physiochemical Characteristics of Hot and Cold Brew Coffee Chemistry: The Effects of Roast Level and Brewing Temperature on Compound Extraction, we see that “…water extraction temperature did not cause differential extraction of CQA isomers.”
Meaning that the temperature of water used to extract coffee did not cause differences in amounts of CGA’s extracted. However, the breakdown of these CGA’s in hot water will increase the TA, and your perceived acidity, of hot brew coffees like iced filter coffee.
And what I found was actually quite interesting ... CGA levels in coffee have the most to do with roasting.
This is the true confirmation for my original theory! They go on to solidify the evidence:
These articles confirm a few key bits of information. First, chlorogenic acids (CGAs) extract relatively quickly from coffee grinds in both hot and cold brew coffees (aka filtered iced coffee vs. cold brew coffee).
Second, as roasting increases, we see a loss in CGA concentration, or acid concentration. This is true for coffee brewed with both hot and cold water. The water temperature, in fact, does not cause a different extraction of chlorogenic acids, it is the roast level that determines the direct amount of acidity each coffee can have.
As we discussed earlier, roast profile definitely plays a significant role in our preferences for Cold Brew VS. Iced Coffee debate.
With this data and information, I’m personally able to conclude that even though people claim and state cold brew is less acidic, that it is in fact not due to the brewing method itself. Instead, this is the result of the degree of roast that is most commonly used for each brewing method.
As discussed above, cold brew commonly uses a dark roast of coffee — with fewer acids in the coffee to begin with — and iced coffee typically using light roasts of coffee, with more acids in it intrinsically.
The difference in acidity between cold brew and iced coffee is mainly due to the roast level typically used for each brewing method.
This is exponentially the case when we think about the perceived acidity. I will agree that iced coffee definitely does taste more acidic than cold brew coffee. I believe this is due to the CGAs being able to break down with hot water, increasing the TA, and our perceived acidity, along with the light roasts of coffee typically used, having more CGAs intrinsically.
Whereas with cold brew, the long extraction time and darker roasts almost exponentially increase the chances of over-extraction, or a bitter taste of the coffee. Nonetheless, the coffee typically used (medium-to-dark roasts) does not have as much acidity intrinsically.
This is in no way factual besides the references used and is my own personal conclusion. Again, I am no scientist, but I have extensively researched coffee and extraction and find it hard to believe that cold brew is innately less acidic due to the brewing temperature.
Please feel free to leave a comment below and provide your own thoughts on these conclusions and on acidity levels in the debate of Cold Brew VS. Iced Coffee!
In Conclusion...
Thus, when brewing iced coffee, the opportunity for nuance in each cup is exponential due to the amount of controllable variables, in tandem with the filter brewing style being known for clarity. This creates an array of possibilities for curating each cup.
Whereas with cold brew coffee, the prolonged brew and filtration method allow for less clarity in the cup while increasing body/texture in the cup.
Listed above are all reasons why, here at DOCR, we prefer to prepare iced coffee. We are able to curate the cup and display our coffees the best we possibly can, with utmost possibility for clarity and complexity in each cup.
Each of us here in the Education Department will stand by our decision to curate quality cups of iced coffee and not cold brew, no matter how long it takes to nail down the recipe!
All this research really provided myself with a new perspective on how we talk about coffee, and the misinformation that is so easily spread. It’s so commonly believed that cold brew is a ‘less acidic” option; however, when you face the facts, some things don’t quite line up.
I am so happy to be able to talk about this long-winded debate! If there are any factors I may have left out, please feel free to comment below. If it's not already obvious, I enjy learning more about coffee, and the science around it. Thank you for allowing me to explore this subject with you all.
Thank you for reading! I hope this helps!
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If you'd like to explore all cited references, see below:
"pH, TA, and acid adjustments" from Winemakers Research Exchange by Beth Chang and Joy Ting
Why Does Cold Brew Taste Different from Barista Hustle, author unknown
Physiochemical Characteristics of Hot and Cold Brew Coffee Chemistry: The Effects of Roast Level and Brewing Temperature on Compound Extraction from National Library of Medicine by Niny Z Rao, Megan Fuller, Meghan D. Grim
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About the writer: Emma LaVoie is the Education Manager for Dessert Oasis Coffee Roasters. She's the brains behind this blog and lit a fire under our team to follow suit. You can almost always find Emma reading a book with a coffee in hand. If you're interested in reaching out to Emma, shoot her an email: emma@dessertoasiscoffee.com. She'd be happy to geek out over coffee with you. (Seriously, don't hesitate to reach out — she'll love it.)