Low acid coffee

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Low acid coffee is any coffee above the critical pH level of 5.5 or has at least 50% less acid than regular coffee without any additives or treatments. [1]

Contents

Regular coffee pH

Low-acid coffee uses non-treated green coffee beans and does not include any additives. It has a lower concentration of acidic compounds, particularly chlorogenic acids, resulting in a higher pH and less acidic taste compared to regular coffee. [2] [3]

The average pH of coffee ranges from 4.85 to 5.1, with a standard deviation of 0.2. Factors influencing the pH variation of coffee (4.9 – 5.3) primarily include the degree of roast. Research from the Latvian Academy of Sciences indicates that the pH varies from 5.0 in light roasts to 5.3 in dark roasts, highlighting roasting color as the most significant determinant of pH in brewed coffee. [4]

Other factors thought to influence coffee's pH include the initial pH of the green coffee bean, varying by type (Arabica or Robusta) and its chemical composition. Arabica beans have a pH between 5.0 and 5.5, while Robusta ranges from 5.3 to 6.0. However, the complex roasting and brewing processes obscure the direct impact of green coffee pH on brewed coffee pH. The consistent pH range in brewed coffee suggests minimal influence from green coffee pH, primarily due to chlorogenic acid compounds formed during roasting. [5]

These conclusions were further explored in 2007 by K. Fujioka and T. Shibamoto of the University of California, Davis. The study which was published in Food Chemistry analyzed the pH and chlorogenic acid content of various commercial coffee brands. [6] The pH of the brewed coffees ranged from 4.95 to 5.99 for regular coffee and from 5.14 to 5.80 for decaffeinated coffee, with the brand exhibiting the highest pH also having the lowest total chlorogenic acid concentration (5.26 mg/g for regular, 2.10 mg/g for decaf). [6] The researchers found a moderate correlation between coffee's pH and its chlorogenic acid content, suggesting that the acidity of coffee is related to the presence of these compounds. [6] The study also indicated that roasting conditions could impact the final chlorogenic acid content and acidity of the brewed coffee, with darker roasts typically having lower levels of chlorogenic acids. [6]

In 2009, a follow-up study conducted by Joon-Kwan Moon, Hyui Sun Yoo, and Takayuki Shibamoto of the University of California, Davis was published in the Journal of Agricultural and Food Chemistry investigated the relationship between the chlorogenic acid content and pH of various coffee samples. [7] The researchers found that the pH of the brewed coffee was correlated with the total chlorogenic acid concentration, with lower chlorogenic acid levels associated with higher pH values (lower acidity). [7] The study also demonstrated that roasting conditions impact the final chlorogenic acid content, with darker roasts (250 °C for 21 minutes) reducing chlorogenic acids by over 99% compared to green coffee beans. [7] The findings suggest that the roasting process can be optimized to produce low-acid coffee while still retaining some level of chlorogenic acids, which have potential health benefits. These roasts successfully lowered their acid levels, departing from the typical coffee pH range of 5.1 ± 0.2 pH. [7] However, as Shibamoto noted, samples from these roasting levels were almost charred and not drinkable, corroborating his 2007 paper's assertion that extreme roasting leads to unpalatable coffee to achieve higher pH levels. This helps explain why commercially brewed coffees do not exceed a pH of 5.3, as the taste becomes unacceptable. [7]

Low-acid coffee

The term "low acid coffee" was first used by Puroast in a 2006 Newsweek article, which compared their coffee to other "stomach-friendly" brands. [8]

In 2015, this prompted another study conducted by Masumi Kamiyama Joon-Kwan Moon, Hae Won Jang, Takayuki Shibamoto of the University of California, Davis was published in the Journal of Agricultural and Food Chemistry investigated the relationship between the degradation of chlorogenic acids, a major component in coffee beans, and the antioxidant activity and acidity of the resulting coffee. [9] The study found that roasting coffee beans at higher temperatures, such as 250 °C, resulted in greater breakdown of chlorogenic acids compared to lower temperatures. This degradation led to the formation of potent antioxidant compounds, including pyrocatechol and 2-methoxy-4-vinylphenol. The study also observed an inverse correlation between the total chlorogenic acid content and the pH of the brewed coffee, with lower chlorogenic acid levels corresponding to higher pH values (lower acidity). These findings suggest that the roasting process, particularly at higher temperatures, plays a role in producing low-acid coffee with increased antioxidant activity. [9] The study involved six typical brands of ground, roasted coffee beans sourced from a local market, identified as brands I through VI. Previous findings highlighted that brand VI had the lowest acidity and the least chlorogenic acid (CQA) content among the brands. Given the strong correlation between CQA levels and antioxidant activity in roasted coffees, four varieties of brand VI (VIa, VIb, VIc, VId) were further examined for their antioxidant potential. Results showed that brand VI, across all its varieties, possessed 5.4 times the antioxidant activity compared to other commercial brands. This higher antioxidant activity was attributed to the high pH (5.99) of brand VI, which promotes the degradation of chlorogenic acids into volatile antioxidants during brewing, unlike coffees with lower pH levels. This supports the idea that higher pH levels in coffee can enhance the formation of beneficial phenolic compounds. [9]

Shibamoto presented his findings at the 246th National ACS convention in Indianapolis, where he received the AFGD Award. [10] It was later confirmed that Brand VI was Puroast Coffee, in a letter released by Shibamoto, well after he presented the published results.

In a 2024 study conducted by Abdulhakim Sharaf Eddin, Philip Junior Yeboah, Salam A. Ibrahim of the North Carolina A&T State University and published in Bioactive Compounds in Health and Disease, researchers investigated the pH and total dissolved solids (TDS) content of 11 commercially available coffee products claiming to be low in acid. [11] The researchers found that the pH values ranged from 4.97 to 5.72, with only one sample having a significantly higher pH (5.72) compared to the others and exceeding the critical pH threshold of 5.5 for beverages. [11] The majority of the samples had pH values between 5.0 and 5.29, which falls within the expected range for regular commercial coffee. The study also noted that factors such as roasting temperature, grind size, bean composition, and extraction time can influence the final pH and TDS of the brewed coffee. [11]

The study found that nearly all tested coffees had high acidity despite labeling claims. The authors recommended establishing standardized definitions for low-acid coffee based on a critical pH of 5.5. Only Puroast Coffee exceeded this pH level, as confirmed by Ibrahim Salam in a publicly released letter.

Health effects

It is particularly beneficial for individuals with sensitive stomachs or conditions like gastroesophageal reflux disease (GERD), as it minimizes gastric discomfort that can be exacerbated by the caffeine and acidity found in regular coffee. [2]

Low acid coffee was originally produced as a smoother gourmet coffee option. It was only discovered as an alternative to regular coffee when its lower acid levels were confirmed in reported studies. [2] Therefore, with a smoother taste profile, it remains a viable option for those seeking to mitigate symptoms such as heartburn, chest pain, and chronic cough associated with GERD. [2] Additionally, increasing awareness of the health impacts of acidic and alkaline foods has led to a broader acceptance of products like low-acid coffee alongside other pH-balanced alternatives. [2]

Exercise has been shown to weaken the lower esophageal sphincter temporarily, increasing the risk of acid reflux. This is particularly relevant when consuming coffee in conjunction with activities such as running, which can exacerbate reflux and induce nausea. [2]

Uses

While not exclusively used in geriatric care, low-acid coffee is often erroneously associated solely with older consumers, overlooking its broader appeal to those with health sensitivities or diagnosed stomach conditions. [2]

Related Research Articles

<span class="mw-page-title-main">Instant coffee</span> Drink made by rehydrating powdered coffee

Instant coffee is a beverage derived from brewed coffee beans that enables people to quickly prepare hot coffee by adding hot water or milk to coffee solids in powdered or crystallized form and stirring. The product was first invented in Invercargill, the largest city in Southland, New Zealand, in 1890. Instant coffee solids refers to the dehydrated and packaged solids available at retail used to make instant coffee. Instant coffee solids are commercially prepared by either freeze-drying or spray drying, after which it can be rehydrated. Instant coffee in a concentrated liquid form, as a beverage, is also manufactured.

<span class="mw-page-title-main">Dutch process cocoa</span> Cocoa that has been treated with an alkalizing agent

Dutch processed cocoa, Dutch cocoa, or alkalized cocoa, is cocoa solids that have been treated with an alkalizing agent to reduce the natural acidity of cocoa, giving it a less bitter taste compared to "natural cocoa" extracted with the Broma process. It forms the basis for much of modern chocolate, and is used in ice cream, hot chocolate, and baking.

<span class="mw-page-title-main">Coffee</span> Brewed beverage made from coffee beans

Coffee is a beverage brewed from roasted, ground coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulating effect on humans, primarily due to its caffeine content. It has the highest sales in the world market for hot drinks.

<span class="mw-page-title-main">Coffee production</span> Industrial process

Coffee production is the industrial process of converting the raw fruit of the coffee plant into the finished coffee. The coffee cherry has the fruit or pulp removed leaving the seed or bean which is then dried. While all green coffee is processed, the method that is used varies and can have a significant effect on the flavor of roasted and brewed coffee. Coffee production is a major source of income for 12.5 million households, most in developing countries.

<span class="mw-page-title-main">Home roasting coffee</span> Roasting coffee beans for personal consumption

Home roasting is the process of roasting coffee from green coffee beans on a small scale for personal consumption. Home roasting of coffee has been practiced for centuries, using simple methods such as roasting in cast-iron skillets over a wood fire and hand-turning small steel drums on a kitchen stovetop.

<span class="mw-page-title-main">Coffee bean</span> Seed of the coffee plant

A coffee bean is a seed from the Coffea plant and the source for coffee. It is the pit inside the red or purple fruit. This fruit is often referred to as a coffee cherry, and like the cherry, it is a fruit with a pit. Even though the coffee beans are not technically beans, they are referred to as such because of their resemblance to true beans. The fruits most commonly contain two stones with their flat sides together. A small percentage of cherries contain a single seed, called a "peaberry". Peaberries make up only around 10% to 15% of all coffee beans. It is a fairly common belief that they have more flavour than normal coffee beans. Like Brazil nuts and white rice, coffee beans consist mostly of endosperm.

<span class="mw-page-title-main">White coffee</span> Number of different kinds of coffees or coffee substitutes

White coffee can refer to any of a number of different kinds of coffees or coffee substitutes worldwide.

Quinic acid is a cyclitol, a cyclic polyol, and a cyclohexanecarboxylic acid. It is a colorless solid that can be extracted from plant sources. Quinic acid is implicated in the perceived acidity of coffee.

<span class="mw-page-title-main">Chlorogenic acid</span> Chemical compound

Chlorogenic acid (CGA) is the ester of caffeic acid and (−)-quinic acid, functioning as an intermediate in lignin biosynthesis. The term chlorogenic acids refers to a related polyphenol family of esters, including hydroxycinnamic acids with quinic acid.

<span class="mw-page-title-main">Caffeic acid</span> Chemical compound

Caffeic acid is an organic compound with the formula (HO)2C6H3CH=CHCO2H. It is a polyphenol. It is a yellow solid. Structurally, it is classified as a hydroxycinnamic acid. The molecule consists of both phenolic and acrylic functional groups. It is found in all plants as an intermediate in the biosynthesis of lignin, one of the principal components of biomass and its residues. It is chemically unrelated to caffeine; the related name is due to its presence in coffee.

<span class="mw-page-title-main">Ferulic acid</span> Chemical compound

Ferulic acid is a hydroxycinnamic acid derivative and a phenolic compound. It is an organic compound with the formula (CH3O)HOC6H3CH=CHCO2H. The name is derived from the genus Ferula, referring to the giant fennel (Ferula communis). Classified as a phenolic phytochemical, ferulic acid is an amber colored solid. Esters of ferulic acid are found in plant cell walls, covalently bonded to hemicellulose such as arabinoxylans. Salts and esters derived from ferulic acid are called ferulates.

<span class="mw-page-title-main">Coffee roasting</span> Process of heating green coffee beans

Roasting coffee transforms the chemical and physical properties of green coffee beans into roasted coffee products. The roasting process is what produces the characteristic flavor of coffee by causing the green coffee beans to change in taste. Unroasted beans contain similar if not higher levels of acids, protein, sugars, and caffeine as those that have been roasted, but lack the taste of roasted coffee beans due to the Maillard and other chemical reactions that occur during roasting.

<span class="mw-page-title-main">Coffee preparation</span> Process of turning coffee beans into a beverage

Coffee preparation is the process of turning coffee beans into liquid coffee. While the particular steps vary with the type of coffee and with the raw materials, the process includes four basic steps: raw coffee beans must be roasted, the roasted coffee beans must then be ground, and the ground coffee must then be mixed with hot or cold water for a specific time (brewed), the liquid coffee extraction must be separated from the used grounds, and finally, if desired, the extracted coffee is combined with other elements of the desired beverage, such as sweeteners, dairy products, dairy alternatives, or toppings.

<span class="mw-page-title-main">Coffee cupping</span> Practice of observing the tastes and aromas of brewed coffee

Coffee cupping, or coffee tasting, is the practice of observing the tastes and aromas of brewed coffee. It is a professional practice but can be done informally by anyone or by professionals known as "Q Graders". A standard coffee cupping procedure involves deeply sniffing the coffee, then slurping the coffee from a spoon so it is aerated and spread across the tongue. The coffee taster attempts to measure aspects of the coffee's taste, specifically the body, sweetness, acidity, flavour, and aftertaste. Since coffee beans embody telltale flavours from the region where they were grown, cuppers may attempt to identify the coffee's origin.

<span class="mw-page-title-main">Torrefacto</span>

Torrefacto refers to a particular process of roasting coffee beans, common in Spain, Paraguay, Portugal, Mexico, Costa Rica, Ecuador, Uruguay and Argentina. The process involves adding a certain amount of sugar during roasting in order to glaze the beans. By adding the additional sugar to the beans it increases the effects of the Maillard reaction during the roasting process, thus giving the beans more of that distinct flavor. The glazed beans are then mixed with normal roasted beans. While originally a cheap way of preserving the coffee beans in the 1920s, due to the common use of low-grade Robusta coffee the process was also used to hide negative aroma and taste characteristics of the coffee.

<span class="mw-page-title-main">Cold brew coffee</span> Coffee made by steeping grounds in cold water

Cold brew coffee, also called cold water extraction or cold pressing, is the process of steeping coffee grounds in water at cool temperatures for an extended period. Coarse-ground beans are soaked in water for about 12 to 24 hours.

Methylpyridinium is an ion with the formula C5H5NCH+3. It is the N-methylated derivative of pyridine. It confers no color to its salts. The ion is classified as an quaternary ammonium ion.

<span class="mw-page-title-main">Ale</span> Type of beer brewed using a warm fermentation method

Ale is a style of beer, brewed using a warm fermentation method. In medieval England, the term referred to a drink brewed without hops.

References

  1. ↑ 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.
  2. 1 2 3 4 5 6 7 Bratskeir, Kate (1 November 2017). "Here's what you should know about low-acid coffee". Mic.
  3. ↑ "Why Does Coffee Bother My Stomach?". Cleveland Clinic.
  4. ↑ 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 .
  5. ↑ Bash, Matthew (May 28, 2024). "Robusta Coffee Acidity Levels Made Easy to Understand". The Coffee Scan.
  6. 1 2 3 4 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.
  7. 1 2 3 4 5 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.
  8. ↑ Newsweek Staff (July 30, 2006). "Lifestyle: Smooth Brew". Newsweek.
  9. 1 2 3 Kamiyama, Masumi; Moon, Joon-Kwan; Jang, Hae Won; Shibamoto, Takayuki (25 February 2015). "Role of Degradation Products of Chlorogenic Acid in the Antioxidant Activity of Roasted Coffee". Journal of Agricultural and Food Chemistry. 63 (7): 1996–2005. Bibcode:2015JAFC...63.1996K. doi:10.1021/jf5060563. PMID   25658375.
  10. ↑ "246TH ACS NATIONAL MEETING" (PDF). cen.acs.org.
  11. 1 2 3 Eddin, Abdulhakim Sharaf; Yeboah, Philip Junior; Ibrahim, Salam A. (8 March 2024). "Evaluating acidity levels in packaged coffee to enhance product label accuracy". Bioactive Compounds in Health and Disease - Online ISSN: 2574-0334; Print ISSN: 2769-2426. 7 (3): 145–151. doi: 10.31989/bchd.v7i3.1303 .
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