What are.... low sulphur, no-added-sulphur, organic and biodynamic wines and why may dairy and egg-sensitive people have problems with wines?
Thanks to Neil Palmer, founder & director of Vintage Roots for the following information:
What is Sulphur dioxide (SO2)?
SO2 is the most widely used additive in wine making, used as an antiseptic to kill of unwanted moulds, bacteria & yeasts, and as an antioxidant to prevent oxygen spoiling the wine. Sulphur derivatives or sulphites naturally occur in wines up to or sometimes over 10 parts per million (ppm), as they are a by-product of the fermentation process. By law, wines containing levels of sulphites over 10ppm must be labelled ‘contains sulphites’.
Why should sulphites be avoided?
Most people are fine with the sulphites in wines, but some people suffer reactions such as headaches, wheeziness, flushing, and a sense of hangover even though only a small amount has been drunk. Some people suffer adverse allergic reactions such as asthma attacks, restricted breathing and closure of the lungs and throat, rashes, hot flushes, diarrhoea and hives. (For more on sulphite allergy see FoodsMatter here.)
Low sulphur and no-added sulphur wines
Low sulphur added (LS) means that the winemakers have added only 50% or less of their maximum allowed level of sulphur: 75mg/litre or less for whites and rosés, and 50mg/litre for reds. No added sulphur (NS) wines have the lowest levels of sulphur anywhere, as none is added, although tiny amounts can be produced as a natural by-product of the fermentation process.
Organic wines generally contain lower levels of sulphites, with some winemakers setting maximum permitted levels of sulphites at 50% of the permitted maximum. No pesticides, herbicides, fungicides or chemical fertilisers are used in organic vinyards and organic wines carry a much lower carbon footprint. They also contain significantly higher levels of resveratrol/antioxidant.
Biodynamic agriculture is more complex than organic as not only does it time the winemaking practices to coincide with cersian phases of the moon so as to work with the earth's natural rhythms, but it uses composts and sprays derived from manure to which minerals and plant/herb extracts (such as nettle, chamomile, dandelion, valerian, silica) have been added, thereby enhancing the life of the soil. It is not a system of winemaking to be undertaken lightly as it requires time, effort and understanding – not to mention patience!
What are vegan (VG) & vegetarian (V) wines?
Winemakers use 'finings' to clarify fermented wine of its sediment – they could wait for the sediment to settle and then draw off the wine from the top, but often taking time is not an option, so agents derived from animal gelatin or fish bladders are used. For those allergic to eggs and dairy, beware!
Some wines suitable for vegetarians use egg white or milk–based products as fining agents. Most wines do contain this information in their ingredients lists, but not all. Vegan wines may therefore be safest for egg or dairy allergic consumers.
For vegan wines, either the wine will be allowed to settle in order that the sediment drops to the bottom, and then the wine will be ‘racked’ off the top, or an inert clay called bentonite will be used as a filter. However,even if you do find a wine labelled clearly, be aware that the winemakers may change their fining agents from vintage to vintage, as different agents give a different quality wine.