03 Mar Sulphur in beer manufacturing
Brewing beer involves microbial activity at every stage, from raw material production and malting to stability in the package. Most of these activities are desirable, as beer is the result of a traditional food fermentation, but others represent threats to the quality of the final product and must be controlled actively through careful management, the daily task of maltsters and brewers globally.
This is where Chemworth come in, as we supply several beer manufacturers to assist with their beer making process.
Chemworth 25kg and 500kg bags of solid sulphur are delivered on site to several beer manufacturers in the UK.
Whilst most beer manufacturers try to stop Sulphur odours in beer, they are most often produced by lager yeasts, although they are produced by ale yeasts as well.
Sulphur odours are usually formed about two to three days into the fermentation. Unlike some of the other flavours and aromas that will be reduced by the yeast, sulphur odours in beer can only escape from the beer by diffusion into the atmosphere. Since some subtle sulphur aroma is a big part of the profile for most lagers, it may be of interest to learn what causes it.
Two of the most important factors in the production of sulphur compounds in lagers are pitching rate and wort original Normally, lower pitching rates and/or high original gravity of the wort will produce more of the sulphur aromas in your beer.
Another factor is yeast nutrient levels in the wort. It seems that worst that are low in the sulphur-containing amino acids will produce more sulphur odours in beer during fermentation.
You won’t normally run into a wort that is deficient in nutrients when making an all-malt beer. It’s when you start adding a lot of adjuncts like corn or rice that you run the risk of having low nutrient levels in your beer.
If you are having problems with sulphury aromas in your high adjunct beers, try adding a yeast nutrient to your wort prior to fermentation. There are some bacteria which can produce sulphury odours. If all else has been eliminated, and you are having problems with sulphur compounds which won’t age out, look at your sanitation procedures. If you are going to brew lagers, a subtle but detectable level of sulphur compounds will always be produced. The best thing you can do is be patient.