The rotten egg smell is from Hydrogen Sulfide (H2S). Sulfite has three oxygen atoms surrounding the sulfur atom (SO3) while sulfate has four oxygen atoms surrounding the sulfur atom (SO4). Both have the same valence (-2). However, in the presence of a a relatively strong acid, sulfite can give off hydrogen sulfide (H2S) and the characteristic rotten egg smell, sulfate won’t because it has more “oxidized” and is a more stable radical. So Rob and Denny are both right here.
By the way, you can quickly resolve sulfury smell in beer by adding copper to the beer. Practically, suspending a short piece of shiny, sanitized copper in beer will convert the offending sulfur form into sulfate. It only takes a few minutes of swishing to do this.
If you often have this sulfury problem, it’s probably a sign that your wort is copper deficient. Put a short length of copper tube in your kettle and leave it there for all future brewing.
Our nose has some receptors that have copper. So due to the affinity of copper and sulfur, we can pick up sulfur compounds in parts per billion down to parts per trillion.
H2S is rotten egg.
SO3 is burnt match.
SO4 is wet drywall.
And yes, some lager yeasts, in particularly 2124, will give off a sulfury smell when fermenting. It scrubs out of the beer during fermentation and the yeast will clean some of it up as well
I just did a “tritbier” yesterday and used 9g of coriander, and 39g of fresh orange zest which is what I got from 3 oranges. I used cara cara oranges which are sweet but I wasn’t really going for traditional since I also added 3 oz of spruce tips.
First taste, first Witbier, actually tastes pretty good,
bad smell all gone.
4.5 Gallon
5 lbs Weyermann German Pilsner Malt
3 lb Briess Red Wheat Malt
8 oz Lightly Crushed Toasted Organic Steel Cut Oats
(50min) ½ oz Centennial-Pellet (8.6%)
(30 min) ½ oz Cluster-Pellet (7.4%)
(5min)10 Grams Coriander, lightly crushed & lightly toasted in frying pan
(5min)10 Grams Organic Dried Sweet Orange Peel
Nottingham
3-week ferment, 4-week bottle condition @73F
Just made a witbier last Wednesday.
47.5% Pilsner Malt
47.5% Flaked wheat
5% rolled Oats
Saaz @ 60’ just to get to 16 ibus
A pinch of coriander @ 5’
And I am making a orange zest extract with vodka, to add at the beer prior to keg.