The natural presence of sulphites in brewing
Sulphites, compounds derived from sulphurous acid, have a long history of use in food and drink preservation due to their antioxidant and antibacterial properties. In brewing, sulphites can originate from two sources: as a natural byproduct of fermentation and, occasionally, as a deliberate additive. In the case of real ale, which is defined by its natural, unfiltered, and unpasteurized nature, the primary source is the yeast itself. During the fermentation process, yeast converts the sulphates naturally present in the brewing water into sulphites. The quantity produced varies depending on factors such as the yeast strain, the specific nutrients available, and fermentation temperature. However, the levels produced by ale yeast are typically very low, often below the 10 parts per million (ppm) threshold that triggers mandatory labelling in many countries.
Unlike real ale, many mass-market beers, particularly lagers, and most wines, have sulphites intentionally added. These additives, such as potassium metabisulphite, act as a preservative, extending the product's shelf life and protecting its flavour from oxidation. For real ale, which is a living product that undergoes a secondary fermentation in the cask and is intended for relatively quick consumption, the need for these chemical preservatives is largely eliminated. The brewer's emphasis is on cleanliness and proper handling to prevent spoilage rather than relying on chemical intervention. This distinction is crucial for understanding why real ale is generally considered a low-sulphite alternative to other alcoholic beverages.
Real ale vs. mass-produced beer: a sulphite comparison
While all beers have some level of naturally occurring sulphites, the brewing process for real ale naturally results in significantly lower total levels. The following table highlights the key differences that affect sulphite content.
| Feature | Real Ale (Cask Ale) | Mass-Produced Keg Beer |
|---|---|---|
| Fermentation | Secondary fermentation in the cask, relying on live yeast. | Process completed at the brewery, often filtered and pasteurized. |
| Sulphite Source | Primarily natural byproduct of ale yeast fermentation. | Natural byproduct plus possible added sulphites for shelf stability. |
| Sulphite Levels | Typically very low, often below 10 ppm. | Can contain higher, added levels, especially in some speciality styles. |
| Filtration | Unfiltered, leaving yeast sediment in the cask. | Often chilled and filtered to remove yeast and other particles. |
| Pasteurization | Unpasteurized, remaining a 'living' product. | Usually pasteurized to kill microorganisms and extend shelf life. |
| Serving | Dispensed via a hand-pull without external CO2. | Served via pressurised kegs with CO2 or nitrogen mix. |
Concerns for those with sulphite sensitivity
For the vast majority of the population, the minimal levels of sulphites in real ale are not a cause for concern. However, for a small percentage of people, particularly asthmatics, sulphites can trigger adverse reactions. Symptoms can include wheezing, chest tightness, coughing, or other allergy-like responses. It is important to note that this is a sensitivity, not a true allergy, as it does not typically involve the immune system in the same way as, for example, a nut allergy. The risk in real ale is low, but sensitive individuals should remain vigilant.
For those with a known sensitivity, it is essential to be aware of the difference between real ale and other beers. While added sulphites are rare in real ale, they are more common in other beers where preservation is a higher priority. Additionally, other allergens such as gluten, nuts, or milk products may be present in certain brews, so checking with the brewer is always the safest option for those with severe sensitivities. The best approach for managing sulphite sensitivity is to know what you are drinking and to be proactive in your choices.
How to ensure a low-sulphite pint
For those looking to minimise sulphite intake, here are some actionable tips:
- Choose real ale: Opt for traditional, cask-conditioned real ales. By definition, these are unpasteurized and unfiltered, and rarely have sulphites added beyond the natural fermentation byproduct.
- Go organic: Some breweries that produce organic or 'no added sulphites' beers may be a safer choice. However, remember that trace amounts will still exist naturally.
- Stick to gin or vodka: If your sensitivity is severe, distilled spirits like gin and vodka contain virtually no sulphites due to the distillation process.
- Talk to the brewer: Many smaller craft breweries are transparent about their ingredients. If you are drinking a brewery-specific beer, asking directly can provide peace of mind.
- Read the label: If you are buying bottled beer, check the label. Regulations require breweries to declare sulphites if they are present at a level of 10 ppm or more.
Conclusion
In summary, real ale contains sulphites, but typically only at very low, naturally occurring levels produced during fermentation. Unlike many commercial beers and wines, real ale is rarely treated with additional sulphites as a preservative. This makes it a generally low-risk choice for individuals with a mild sulphite sensitivity. For those with more severe reactions, awareness of brewing processes and checking with the brewery for ingredient information remains the best course of action. Overall, enjoying a pint of real ale means appreciating a naturally conditioned, living product with a minimal, unadulterated sulphite profile.
For more detailed information on sulphite sensitivity, please visit the official website of Anaphylaxis UK.
