The 2019 U.S. PIRG Study and What It Found
In February 2019, the U.S. Public Interest Research Group (PIRG) released a report titled "Glyphosate pesticide in beer and wine," which detailed the results of its independent testing. The study tested 15 popular beer brands and five wines for the presence of glyphosate, the active ingredient in the herbicide Roundup. Shockingly, the chemical was detected in all but one of the samples.
The report specified that Guinness Draught contained approximately 20.3 parts per billion (ppb) of glyphosate. While this is a low concentration, and both industry representatives and the EPA pointed out it was far below daily exposure limits, the report's authors and critics highlighted concerns over the chemical's ubiquitous nature and potential long-term, low-dose health effects. According to the World Health Organization's International Agency for Research on Cancer (IARC), glyphosate is a "probable carcinogen," although other regulatory bodies have disagreed with this classification. The study's findings brought to light the possibility of widespread pesticide contamination in consumer products, even those produced by major brands.
How does glyphosate get into the beer?
Glyphosate is not directly added to beer during the brewing process. Its presence is linked to the agricultural practices used to grow the raw ingredients, specifically barley. In conventional farming, glyphosate is sometimes used as a desiccant, or drying agent, on grain crops shortly before harvest to kill weeds and speed up the drying process.
During the malting process, where barley is soaked in water to initiate sprouting, any glyphosate residue on the grain can persist. Furthermore, environmental factors can contribute to contamination. Pesticide drift from nearby fields can affect organic crops that do not use the herbicide, as evidenced by the detection of glyphosate in some organic beers tested by PIRG.
Guinness's brewing process uses four key ingredients: water, barley, hops, and a unique yeast strain. To produce its characteristic dark colour, a portion of the barley is roasted. Historically, the brand has been committed to the quality of its source ingredients. In modern times, and partly in response to growing consumer demand for sustainability, Guinness's parent company, Diageo, has launched significant initiatives to work with its agricultural partners to improve farming methods and reduce environmental impact.
Glyphosate Levels in Guinness vs. Other Beers
The 2019 PIRG study offered a snapshot of glyphosate levels across various brands, providing a useful comparison. The results showed a range of contamination, with some brands having higher levels than Guinness. Peak Beer Organic IPA was the only sample tested with no detectable levels of the chemical.
| Beer Brand | Glyphosate Level (ppb) |
|---|---|
| Tsingtao Beer | 49.7 |
| Coors Light | 31.1 |
| Miller Lite | 29.8 |
| Budweiser | 27.0 |
| Corona Extra | 25.1 |
| Heineken | 20.9 |
| Guinness Draught | 20.3 |
| Stella Artois | 18.7 |
| Sierra Nevada Pale Ale | 11.8 |
| Samuel Smith's Organic Lager | 5.7 |
| Peak Beer Organic IPA | Not Detected |
Table based on 2019 U.S. PIRG study results.
Health Implications and Conflicting Reports
Public concern over glyphosate stems from its classification by the IARC in 2015 as a "probable human carcinogen," following a meta-analysis of epidemiological studies. This classification has been a point of significant controversy, particularly with non-Hodgkin lymphoma claims. However, regulatory bodies like the U.S. Environmental Protection Agency (EPA) and the European Food Safety Authority (EFSA) have typically held that glyphosate is not likely to be carcinogenic to humans at environmentally relevant doses.
The brewing industry and parent company Bayer (which acquired Monsanto) have consistently maintained that the trace levels found in products are not a health risk. One industry spokesperson noted that an adult would need to consume an unrealistic volume of beer per day to reach a level considered a significant health risk.
Long-Term Low-Dose Exposure Controversy
The crux of the debate lies in the long-term effects of low-dose exposure. Consumer advocates and some scientists argue that regulatory standards are often based on large, acute exposures and may not adequately address the cumulative impact of constant, low-level exposure to chemicals like glyphosate over a person's lifetime. The pervasive nature of the chemical in the environment, from agricultural runoff to air pollution, makes complete avoidance difficult. While no conclusive link has been proven for the trace amounts found in beer, the public remains wary.
Guinness's Modern Commitment to Sustainability
Guinness, owned by beverage giant Diageo, has publicly addressed sustainability and its agricultural supply chain. While not directly referencing the 2019 study's findings, the company's initiatives point toward a desire to control the quality of its raw materials from the ground up.
Key sustainability actions by Diageo and Guinness include:
- Regenerative Agriculture Pilot: Guinness launched an ambitious pilot program in Ireland involving 44 barley farmers to test and implement regenerative farming practices. These methods aim to improve soil health, increase biodiversity, and sequester carbon, which inherently promotes a healthier farming ecosystem.
- Long-Term Goals: As part of Diageo's "Society 2030: Spirit of Progress" plan, the company has set ambitious targets for sustainability. These include achieving net zero carbon in its direct operations by 2040 and working with suppliers to promote sustainable practices throughout the supply chain.
- Water Management: A crucial ingredient in Guinness, water is carefully managed. The Dublin brewery uses water sourced from the Wicklow mountains and has significantly reduced its overall water usage.
These initiatives, particularly the focus on regenerative agriculture for barley, suggest a proactive approach to addressing the very issue of potential pesticide exposure at the source of its ingredients. By focusing on sustainable and healthier farming, Guinness can better control the quality of its barley and, by extension, its final product.
Conclusion: Does Guinness Still Have Glyphosate?
While a 2019 study did detect trace levels of glyphosate in Guinness, the amounts were minimal and considered within safe regulatory limits by agencies like the EPA. The contamination is likely a reflection of widespread agricultural practices involving glyphosate, rather than specific wrongdoing by the brewer. Since the 2019 report, Guinness has increased its focus on regenerative farming and sustainability, directly addressing concerns about its supply chain and raw ingredient quality. It is reasonable to infer that these new practices are aimed at reducing or eliminating such residues. For consumers concerned about the long-term impact of low-dose pesticide exposure, supporting brands that emphasize organic or sustainable sourcing, such as Guinness's regenerative farming efforts, is a tangible step. The ultimate decision rests with the consumer, who must weigh the trace risk against the pleasure of the product, armed with the knowledge of where their beer comes from.
PIRG Education Fund: Glyphosate pesticide in beer and wine
The Brewing Process and Contamination Risk
The primary pathway for glyphosate to enter beer is through the malted barley. As glyphosate is a common agricultural tool for weed control and crop desiccation, any barley grown using conventional methods is susceptible to containing low-level residues. The brewing process does not typically eliminate these residues entirely. However, the exact amount can vary widely depending on the farming practices, environmental conditions, and the specific barley crop. The discovery of residues even in some organic beers highlights the pervasive nature of environmental cross-contamination, making it difficult for even the most stringent producers to completely guarantee a glyphosate-free product. This issue underscores the need for industry-wide shifts towards more sustainable and organic farming methods, which Guinness is exploring through its regenerative agriculture initiatives.
