Low acid coffee
Low-acid coffee refers to coffee that has a reduced level of acidic compounds or a higher pH compared to regular coffee. There is no standardized definition, but low-acid coffee is often classified as having a pH above 5.0, with some sources suggesting a threshold of 5.5.[1] Some brands define low-acid coffee by a reduction in titratable acidity, which measures total acid concentration rather than pH alone.[2]
Regular coffee pH
[edit]The pH of regular brewed coffee typically ranges between 4.85 and 5.1, with a standard deviation of 0.2, though factors such as roast level, bean variety, and brewing method influence acidity.[2]
Research from the Latvian Academy of Sciences found that the pH of coffee generally ranges from 5.0 in light roasts to 5.3 in dark roasts, highlighting roasting color as a significant determinant of pH.[3]
Other factors thought to influence coffee's pH include the initial pH of the green coffee bean, which varies by type:
- Arabica beans have an unroasted pH between 5.0 and 5.5.
- Robusta beans have a slightly higher pH, ranging between 5.3 and 6.0.
However, the roasting and brewing process alters these values significantly. Studies indicate that the pH of green coffee has minimal impact on brewed coffee due to the formation of chlorogenic acids during roasting.[4]
Roasting and acidity correlation
[edit]A 2007 study by K. Fujioka and T. Shibamoto of the University of California, Davis, published in Food Chemistry, analyzed the pH and chlorogenic acid content of commercial coffee brands.[5] The study found:
- The pH of regular brewed coffee ranged from 4.95 to 5.99.
- Decaffeinated coffee had a slightly higher pH range of 5.14 to 5.80.
- Brands with the highest pH levels had the lowest chlorogenic acid content (5.26 mg/g for regular, 2.10 mg/g for decaf).
A 2009 follow-up study conducted by Joon-Kwan Moon, Hyui Sun Yoo, and Takayuki Shibamoto, also at the University of California, examined the relationship between roasting conditions and coffee acidity.[6] The study found that:
- Darker roasts (250 °C for 21 minutes) reduced chlorogenic acids by over 99% compared to green coffee beans.
- Roasting conditions significantly impacted pH, with lower chlorogenic acid levels correlating with higher pH values.
- Excessively dark roasting made coffee unpalatable, which is why most commercially brewed coffees do not exceed pH 5.3.
Health effects
[edit]Low-acid coffee has been marketed as beneficial for individuals with acid reflux, gastroesophageal reflux disease (GERD), or sensitive stomachs. Some studies suggest that reducing coffee acidity may minimize gastric discomfort, but other factors—such as caffeine content, brewing method, and individual tolerance—also influence how coffee affects digestion.[2]
Exercise has been shown to temporarily weaken the lower esophageal sphincter, increasing the risk of acid reflux. This is particularly relevant when coffee is consumed before activities such as running, which can exacerbate reflux symptoms.[2]
Uses
[edit]Low-acid coffee is primarily marketed to individuals with digestive sensitivities, though it is also consumed by those who prefer a milder taste. Some endurance athletes and fitness enthusiasts consume low-acid coffee before exercise to reduce the risk of acid reflux during activity.[2]
References
[edit]- ^ Chow, Laurence C. (July 2010). "Diffusion of ions between two solutions saturated with respect to hydroxyapatite: A possible mechanism for subsurface demineralization of teeth". Journal of Research of the National Institute of Standards and Technology. 115 (4): 217–224. doi:10.6028/jres.115.015. PMC 2966276. PMID 21037801.
- ^ a b c d e Bratskeir, Kate (1 November 2017). "Here's what you should know about low-acid coffee". Mic.
- ^ Laukalēja, Ilze; Krūma, Zanda; Cinkmanis, Ingmars (February 2022). "Impact of The Roast Level on Chemical Composition of Coffee from Colombia". Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. 76 (1): 145–151. doi:10.2478/prolas-2022-0022.
- ^ Bash, Matthew (May 28, 2024). "Robusta Coffee Acidity Levels Made Easy to Understand". The Coffee Scan.
- ^ Fujioka, K.; Shibamoto, T. (January 2008). "Chlorogenic acid and caffeine contents in various commercial brewed coffees". Food Chemistry. 106 (1): 217–221. doi:10.1016/j.foodchem.2007.05.091.
- ^ Moon, Joon-Kwan; Yoo, Hyui Sun; Shibamoto, Takayuki (24 June 2009). "Role of Roasting Conditions in the Level of Chlorogenic Acid Content in Coffee Beans: Correlation with Coffee Acidity". Journal of Agricultural and Food Chemistry. 57 (12): 5365–5369. Bibcode:2009JAFC...57.5365M. doi:10.1021/jf900012b. PMID 19530715.
