Cold brew coffee, a relatively recent trend in the coffee industry, has captured the attention of coffee enthusiasts. This article delves into the potential diet benefits of cold brew coffee, examining its production methods, sensory properties, and chemical composition.
What is Cold Brew Coffee?
Cold brew coffee is prepared by steeping coffee grounds in cold water for an extended period, typically 12-24 hours. This contrasts with traditional hot brewing methods, where hot water is used to extract flavor and caffeine from coffee beans. The cold brew method results in a beverage that is often perceived as less bitter and acidic than hot brewed coffee.
While cold brew has gained popularity in recent years, it is not a completely new concept. In the 17th century, the Dutch introduced this preparation method to Japan. In the USA, Toddy was one of the first cold brew system producers, starting in the 1960s.
Production Methods and Variables
Unlike hot brewed coffee, there is no standardized production process for cold brew coffee. Several parameters can influence the final product, including:
- Extraction Time: The duration of steeping, which can range from several hours to over a day.
- Extraction Temperature: While cold water is used, the specific temperature can vary.
- Coffee-to-Water Ratio: The amount of coffee grounds used per liter of water.
- Turbulence: The degree of agitation during the extraction process.
- Water Composition: The mineral content and pH of the water.
- Bean Type: The variety of coffee bean used (e.g., Arabica, Robusta).
- Grind Size: The fineness of the coffee grounds.
- Roasting Level: The degree to which the coffee beans have been roasted.
A survey of cold brew producers revealed a preference for medium roasted Arabica coffee, using 50-100 g/L at 8 °C for approximately one day. However, there is considerable variability in these practices.
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Experimentation with Extraction Parameters
To understand the influence of various parameters, experiments have been conducted to analyze the extraction process.
- Experiment A: Used 260 ± 5 g of coarsely ground beans, with 240 ± 2 g then poured into a 5 L darkened glass container. Three liters of water were added, which had previously been tempered to 23 °C room temperature in a measuring beaker.
- Experiment B: Three different cold brews were made from the same beans, using 240 g of roasted and ground beans poured into 5 L amber glass bottles with 3 L of drinking water. One bottle was left undisturbed, another was placed in an ultrasonic bath, and the third was placed on a shaking table at 125 Hz.
Chemical Analysis with NMR Spectroscopy
Nuclear magnetic resonance (NMR) spectroscopy has been used to analyze the chemical composition of cold brew coffee. This technique can identify and quantify various compounds, including:
- Formic acid
- Chlorogenic acid
- Caffeine
- Acetic acid
- 5-Hydroxymethylfurfural (HMF)
- Lactic acid
- Trigonelline
NMR analysis has revealed potential chemical differences between cold brew and hot brew coffee. Principal component analysis (PCA) of NMR spectra can differentiate between the two extraction methods.
Sensory Evaluation
Sensory testing, including ranking and triangle tests, has shown that some people prefer cold brew over iced coffee (cooled-down hot-extracted coffee). However, sensory properties are influenced by the production process.
Microbiological Considerations
A survey of 23 different cold brew coffee samples from coffee shops in southern Germany examined the presence of microorganisms. The samples were tested for spoilage and health risks, such as aerobic lactic acid bacteria, yeasts, hygiene indicators (Enterobacteriaceae, Pseudomonas spp., and coagulase-positive Staphylococcus), potentially pathogenic germs (presumptive Bacillus cereus), and pathogens (Listeria monocytogenes and Salmonella spp.), as well as molds.
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Potential Diet Benefits of Cold Brew Coffee
Cold-brew coffee may have several health benefits, like boosting metabolism and protecting heart health. Some people find cold-brew coffee is more gentle on the stomach than other types of coffee.
1. May Boost Your Metabolism
Metabolism is the process by which your body uses food to create energy. The higher your metabolic rate, the more calories you burn at rest. Just like hot coffee, cold brew coffee contains caffeine, which has been shown to increase your resting metabolic rate by up to 11%.
Caffeine appears to boost metabolic rate by increasing how quickly your body burns fat. In a study in 8 men, ingesting caffeine led to a 13% increase in calorie burning, as well as a 2-fold increase in fat burning - much greater effects than they experienced after taking a placebo or beta-blocker (medication for blood pressure and circulation).
The caffeine in cold brew coffee can increase how many calories you burn at rest. This may make it easier to lose or maintain weight.
2. May Lift Your Mood
The caffeine in cold brew coffee may improve your state of mind. Caffeine consumption has been shown to enhance mood, especially among sleep-deprived individuals.
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A review of studies in over 370,000 people found that those who drank coffee had lower rates of depression. In fact, for every cup of coffee consumed per day, depression risk sank by 8%.
Some research even suggests that caffeine could be used as a nutritional supplement to boost mood and brain function in older adults. In a study in 12 adults ages 63-74, taking 1.4 mg of caffeine per pound (3 mg per kg) of body weight improved mood by 17%. This amount of caffeine is equivalent to around two cups of coffee for the average-sized person. Caffeine also improved their ability to react to an object moving toward them, indicating that it increases focus and attentiveness.
Drinking cold brew coffee may boost your mood, reduce your risk of depression, and improve brain function.
3. May Lower Your Risk of Heart Disease
Heart disease is a general term for several conditions that can affect your heart, including coronary artery disease, heart attack, and stroke. It’s the number one cause of death worldwide.
Cold brew coffee contains compounds that may reduce your risk of heart disease, including caffeine, phenolic compounds, magnesium, trigonelline, quinides, and lignans. These increase insulin sensitivity, stabilize blood sugar, and lower blood pressure. The drink also contains chlorogenic acids (CGAs) and diterpenes, which act as antioxidants and anti-inflammatory agents.
Drinking 3-5 cups of coffee (15-25 ounces or 450-750 ml) daily may lower your risk of heart disease by up to 15%, compared to people who don’t drink coffee.
Evidence to suggest that drinking more than 3-5 cups per day increases heart disease risk is lacking, though this effect has not been studied in people who consume more than 600 mg of caffeine per day, the equivalent of about 6 cups of coffee.
That said, people with uncontrolled high blood pressure should avoid drinking caffeine regularly, as this may further elevate their levels.
Regularly drinking cold brew coffee may improve your heart health. However, caffeine should be limited or avoided if you have uncontrolled high blood pressure.
4. May Lower Your Risk of Type 2 Diabetes
Type 2 diabetes is a chronic condition in which your blood sugar levels are too high. If left untreated, it can lead to many serious health complications.
Cold brew coffee may reduce your risk of developing this disease. In fact, drinking at least 4-6 cups of coffee per day is associated with a lower risk of type 2 diabetes.
These benefits may be largely due to chlorogenic acids, which are powerful antioxidants in coffee. Cold brew coffee may also regulate gut peptides, which are hormones in your digestive system that control and slow digestion, keeping your blood sugar stable.
One study in over 36,900 people ages 45-74 found that those who drank at least 4 cups of coffee per day had a 30% lower risk of type 2 diabetes than individuals who didn’t drink coffee daily. A review of 3 large studies in more than 1 million people found that those who increased their coffee intake over 4 years had an 11% lower risk of type 2 diabetes, compared to a 17% higher risk in those who reduced their coffee intake by more than 1 cup per day.
Regularly drinking cold brew coffee may help keep your blood sugar stable and reduce your risk of type 2 diabetes.
5. May Reduce Your Risk of Parkinson’s and Alzheimer’s Disease
In addition to increasing your attentiveness and mood, cold brew coffee may benefit your brain in other ways. Caffeine stimulates your nervous system and may affect how your brain functions. One recent study observed that drinking coffee can protect your brain from age-related diseases.
Alzheimer’s and Parkinson’s diseases are neurodegenerative conditions, which means they are caused by brain cell death that occurs over time. Both illnesses can result in dementia, a decline in mental health that makes daily activities difficult. Alzheimer’s disease is marked by significant memory impairment, while Parkinson’s often causes physical tremors and stiffness.
One observational study found that people who drank 3-5 cups of coffee per day during mid-life had a 65% lower risk of developing dementia and Alzheimer’s in old age. Another observational study noted that coffee drinkers have a lower risk of Parkinson’s disease. In fact, men who drink more than four cups of coffee per day are five times less likely to develop this condition.
It appears that several compounds in coffee, such as phenylindanes, as well as harman and nonharman compounds, provide protection against Alzheimer’s and Parkinson’s disease.
Keep in mind that decaffeinated coffee doesn’t appear to offer the same protective benefits as caffeinated varieties.
Cold brew coffee contains compounds called phenylindanes, as well as lower amounts of nonharman and harman compounds. These can help protect your brain from age-related diseases.
6. May Be Easier on Your Stomach Than Hot Coffee
Many people avoid coffee because it’s an acidic beverage that may stimulate acid reflux.
Acid reflux is a condition in which stomach acid frequently flows from your stomach back into your esophagus, causing irritation.
The acidity of coffee also tends to be blamed for other ailments, such as indigestion and heartburn.
The pH scale measures how acidic or alkaline a solution is from 0 to 14, with 7 being neutral, lower numbers more acidic, and higher numbers more alkaline.
Cold brew and hot coffee generally have similar acidity levels, around 5-6 on the pH scale, though this can vary depending on individual brews. Still, some studies have found cold brew to be slightly less acidic, which means it may irritate your stomach less. Another reason why this beverage may be less irritating than hot coffee is its content of crude polysaccharides. These carbohydrates, or chains of sugar molecules, boost the immunity of your digestive system. This may decrease gut irritation and the bothersome effects of coffee’s acidity on your stomach.
Cold brew coffee is only slightly less acidic than hot coffee but contains compounds that may protect your stomach from this acidity. As such, it may cause fewer unpleasant digestive and acid reflux symptoms than hot coffee.
7. May Help You Live Longer
Drinking cold brew coffee may reduce your overall risk of death, as well as dying from disease-specific causes. A long-term study in 229,119 men and 173,141 women ages 50-71 found that the more coffee people drank, the lower their risk of death from heart disease, respiratory disease, stroke, injuries, accidents, diabetes, and infections.
One reason for this association may be that coffee is high in antioxidants. Antioxidants are compounds that help prevent cell damage that can lead to chronic illnesses like heart disease, type 2 diabetes, and cancer. These conditions can significantly reduce your lifespan. Though studies show that hot coffee contains more total antioxidants than cold brew varieties, the latter packs some very potent antioxidants, such as caffeoylquinic acid (CQA).
Though cold brew coffee contains fewer total antioxidants than hot coffee, it’s full of compounds that have high antioxidant activity. Antioxidants help prevent diseases that can reduce your lifespan.
8. Similar Caffeine Content to Hot Coffee
Cold brew coffee is made as a concentrate that’s meant to be diluted with water, usually in a 1:1 ratio. The concentrate is incredibly strong on its own. In fact, undiluted, it provides about 200 mg of caffeine per cup.
However, diluting the concentrate - as is customary - reduces the caffeine content of the final product, bringing it closer to that of regular coffee.
Though caffeine content can vary depending on the brewing method, the difference in caffeine content between hot coffee and cold brew is insignificant. The average cup of hot coffee contains around 95 mg of caffeine, compared to about 100 mg for a typical cold brew.
Cold brew and hot coffee contain similar amounts of caffeine. However, if you drank cold brew coffee concentrate without diluting it, it would provide about twice the caffeine.
9. Very Easy to Make
You can easily make cold brew coffee at home.
First, purchase whole roasted coffee beans locally or onlineand coarsely grind them.
Add 1 cup of grounds to a large jar and gentlystir in 4 cups of water.