When we first became enamored with cold brew coffee. It was widely accepted that cold brew coffee had half the acidity of hot brewed coffee.
As more scientific studies are completed, this selling point may no longer be valid. In regards to the caffeine, as explained in our previous journal, concentrations were slightly higher it was not 2-3 times as high. When it comes to acidity it is being found that there is not as much of a difference as hot brewed coffee. Which led us to this journal. We love cold brew coffee but we want to make sure we are always reporting on what the true benefits are when you consume cold brew coffee.
So how is the acidity of coffee represented? The acidity is determined by the measurements conducted on the pH scale. pH is a scale of acidity from 0 to 14. It tells how acidic or alkaline a substance is. More acidic solutions have lower pH. More alkaline solutions have higher pH. Substances that aren't acidic or alkaline (that is, neutral solutions) usually have a pH of 7. In general black coffee is 5 on the pH scale (more acidic).
In a 2017 study by Niny Rao and Megan Fuller “The Effect of Time, Roasting Temperature, and Grind Size on Caffeine and Chlorogenic Acid Concentrations in Cold Brew Coffee”, “3-CGA concentrations and pH were comparable between cold and hot brews. This work suggests that the difference in acidity of cold brew coffee is likely not due to 3-CGA or caffeine concentrations considering that most acids in coffee are highly soluble and extract quickly.” The pH results for the cold brew coffee and hot brew coffee where 5.x.
According to a more recent study “Acidity and Antioxidant Activity of Cold Brew Coffee”
published by Niny Z. Rao and Megan Fuller from the Department of Chemistry and Biochemistry at Thomas Jefferson University, East Falls Campus in Philadelphia , “The pH values of the cold and hot brew samples were found to be comparable, ranging from 4.85 to 5.13.”
Although there are minor differences between the pH readings of cold brew vs hot brew coffee, usually these differences fall within a standard deviation making them negligible.
Given the results from these recent studies it would be safe to say that cold brew coffee is not half as acidic as hot brew coffee. It might be a little less acidic but it is not half…
With the rising popularity of cold brew coffee, we are sure there will be more studies conducted and in time there will be an agreed upon answer of whether the pH levels are relatively the same between cold brew coffee and hot brew coffee.
Fuller, Megan, and Niny Z Rao. “The Effect of Time, Roasting Temperature, and Grind Size on Caffeine and Chlorogenic Acid Concentrations in Cold Brew Coffee.”Scientific Reports, Nature Publishing Group UK, 21 Dec. 2017,www.ncbi.nlm.nih.gov/pmc/articles/PMC5740146/.
Rao, Niny Z, and Megan Fuller. “Acidity and Antioxidant Activity of Cold Brew Coffee.”Scientific Reports, Nature Publishing Group UK, 30 Oct. 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC6207714/.