Beer with Metabisulphite rinse

An interesting question.

1- metabisulphite is usually regarded as an oxygen scavenger and thus a preservative by virtue of inhibiting bacterial (and yeast) growth (but not so much the metabolism). Metabisulphite in solution can also be a source of SO2 - which reacts in water to make an acid solution. That acidic solution could be regarded as acting something like StarSan (which is a solution of phosphoric acid and a surfactant/detergent). It can sterilise as it has antimicrobial activity. But I would not class it as a strong sterilising agent. For for most intents and purposes it is a reasonably viable one for treating unsoiled equipment. However I can imagine situations when it might not sterilise completely.

2- a very small residue left on the equipment is no particular cause for concern. After all people add whole tablets to wine ferments. It could be wiped or rinsed off as preferred. One could use boiling water and one could probably use cold tap water if one particularly wanted to remove it.

3- you can continue using metabisulphite if it works for you. It has worked for millions of baby feeding bottles over the years and is still used widely when making wine. If the brewing equipment is unsoiled and well scrubbed down then using "campden tablets" is a viable option. As I have said IMHO it is not totally dissimilar to StarSan in action. If the equipment becomes soiled or a biofilm begins to build up then it might well be better using a deep cleaning agent like VWP or similar.

1) Yes, it's true. It's not a sanitizer.

2) This is dry sodium or potassium as a by product after absorbing oxygen. Can give off flavors.

3) NO

Metabisulfites (potassium and sodium) are not sanitizers. They're actually preservatives. They work by depleting solutions of oxygen to prevent aerobic organisim growth. They don't kill anything on contact as a sanitizer does.

For an example of how it works, get some Apple juice that has it as a presevative. If you pitch yeast in it, there will be no cell growth but the existing yeast will consume sugars. The preservative can be defeated with oxygenating the juice and then the yeast will have a growth phase.

1- It is used to sanitize equipment for wine making, it should be strong enough for beer IMO.

2- If you leave the residue, it could leave an after taste. I would rinse it.

3- I use metabisulfite to sanitize when I make wine and a one step cleaner/sanitizer (Aseptox) when I make beer.

Sulfite residue can have a harsh taste which is ok in wine since it will age longer and serve as an anti-oxidant, but in beer I prefer something that will leave no aftertaste. People widely use Starsan, but there are other similar products, the one I use come in powder that you mix with water which is a lot cheaper than buying it in liquid form.

It's kind of a poor sanitizer in general with that concentration. It's not that it is bad for beer, it takes 5 minutes to sanitize. It will work, but you're going to have to be extra patient and careful. Trying to use the rest will have not paid off if you ruin one batch.

Buy a bottle of star-san and keep the metabisulphite for when you want some non-acidic anti-oxidant.

Let me answer your questions...

1. metabisulfites (potassium and sodium) in strong enough concentrations can be a very effective sanitizer. In stronger doses, potassium metabisulfite works well to sanitize your equipment, with no negative consequences. Make a solution of 8 teaspoons dry measure of potassium metabisulfite added to 1 gallon (4 liters) of warm water. Rinse your equipment in this solution for about 5 minutes, and let drip dry.

2. You didn't probably dissolve it enough. But, you can rinse it with boiled water to remove it because that white residue is probably enough to kill off your yeast.

3. I would continue to use sulfites to preserve your cider but there are much better sanitizing cleaners than sulfites. I recommend using PBW or StarSan instead.