Last year I bought 1 pound bag of K-meta. It was stored with my other wine making stuff in a bin in the garage. I just went to make a fresh batch of stock K-Meta solution (10g/100ml water) for must dosing and I noticed that the powder had more or less solidified into a solid lump. I made up 200ml of solution and it has a slight yellowish tint and it does not seem to have particularly strong smell. A batch of K-Meta sanitizing solution I made up over the winter still has the characteristic strong odor. That stuff is mixed at 3tsp per gallon of water. Could my K-Meta powder have gone bad?
Can K-meta powder go bad?
- Thread starter rhodesengr
- Start date
Help Support Winemaking Talk - Winemaking Forum:
If it were exposed to moisture, heat, light and oxygen, it could lose its potency. I would pitch it and get a new supply. Small cost, huge reward.
Yeah but I was going to use it tomorrow. No light exposure. It was in its original opaque bag and that was in another ziplock. But it's been hot the last two weeks.
Ohio Bob
Senior Member
For sanitizing it should work, if you’re worried then double the dosage.
Sorry, I missed the part that you were using it for sanitizing. As OhioBob says, make up a very strong solution (one that will curl you nose hair) even if you use 6 T per gallon. In sanitizing equipment, not bottles, I always rinse after using the K-meta solution.
Sorry if I confused y'all. What I made up today would be to put in the must to kill the wild yeast on my plums. What I was saying is that I also have a bottle of solution I made up a few months ago for sanitizing bottles. That batch still has a nice strong odor. I was comparing the 3tsp solution to the 10g/100ml solution I just tried to make with the lumpy Kmeta.
Amazon is supposedly delivering some new Kmeta tomorrow. Wondering if I can dose with the potentially weak stuff in the morning when I set up the must and then dose again later in the day when the new Kmeta arrives.
Amazon is supposedly delivering some new Kmeta tomorrow. Wondering if I can dose with the potentially weak stuff in the morning when I set up the must and then dose again later in the day when the new Kmeta arrives.
* In the old days grandpa would make country wine without K meta. You don’t have to kill / or stunt 90% of the organisms to make a wine. Commercial yeast tends to be selected to overpower native yeast.
* Humidity will react with meta to release the SO2. If this was serious you should have smelled it when in that room. Smell is a good indicator of how much SO2 can be produced.
* Metabisulphite is produced in a pyrolysis reaction. I am surprised to hear it formed a block after high temperatures.
Yes it could have gone bad. Again humidity or water. I would look for a tighter container. An example might be the plastic canister that ground coffee comes in. Wider mouth glass with a plastic lid should also be good. Metal should be avoided.
* Humidity will react with meta to release the SO2. If this was serious you should have smelled it when in that room. Smell is a good indicator of how much SO2 can be produced.
* Metabisulphite is produced in a pyrolysis reaction. I am surprised to hear it formed a block after high temperatures.
Yes it could have gone bad. Again humidity or water. I would look for a tighter container. An example might be the plastic canister that ground coffee comes in. Wider mouth glass with a plastic lid should also be good. Metal should be avoided.
sulphite is destroyed by moisture in combination with oxygen
K-Meta is usually mixed 3 TBLS per gallon of water for use as a sanitizing solution.
When you rinse after sanitizing, you risk contaminating the equipment, bottles, etc. According to Tim Vandergrift, a few seconds after draining bottles of K-Meta, there is a miniscule amount of SO2 left and rinsing serves no purpose other than to risk the possibility of contaminating the sanitized surfaces.
Tim Vandergrift! What the heck does he know?!
For bottles, we use one of these spritzers, with sanitizing solution and then hang them on a tree to drain. I always assumed that a trace amount of K-meta would remain in the bottle.
Once the bottle is filled and the cork is inserted, it is a "closed system" and I am less concerned about contamination.
As regards equipment, I have a spray bottle that I use on things like hoses, syphons, hydrometers, etc. or in the case of carboys, I slosh a cup or so inside the carboy before filling it. In addition to that, I am usually racking and sulfiting, so I add 1/4 t. to the carboy before filling.
Yeah, it sounds like your K-Meta powder might have absorbed some moisture and turned into a lump. I had a similar issue once where my powder clumped up and didn’t smell as strong. If your new solution doesn’t have the usual strong odor and has a yellowish tint, it might not be as effective. I’d suggest getting a new batch and storing it in a moisture-proof container.
- Joined
- Sep 12, 2018
- Messages
- 1,501
- Reaction score
- 880
Doesn’t rinsing defeat the purpose?
Ohio Bob
Senior Member
In my opinion it does defeat the purpose. I use an idophor solution to sanitize, and no rinsing.
- Joined
- Sep 12, 2018
- Messages
- 1,501
- Reaction score
- 880
San Star or kmeta solution no rinsing. Never a problem.
I don't feel that it does and I have been doing it this way for about 60 years, when I first became aware of Sodium Meta-bisulfite. I later switched to Potassium Meta-bisulfite. Here is a blurb from Wine Maker website:
"Final Rinse
Some non-toxic sanitizing agents (see later) do not require a water rinse; however, a final water rinse is always a good idea. If your municipal water contains too much chlorine, an inexpensive carbon water filter can be used to remove the chlorine, but bear in mind that once the chlorine has been removed, there is nothing to prevent microorganisms from proliferating downstream from the carbon filter. Keep that part of your plumbing short and clean.After the final rinse, drain your equipment thoroughly and ensure that it is free of odors. If an odor lingers, you might try filling the carboy, or similar equipment, with cold, odor-free water to displace all the air, then drain it and check again for odors. If they persist, cleaning should be repeated."
Everyone should do what makes them comfortable. This works for me and I have never had a problem.
I worry a little about the very low pH of Star San affecting my pH determinations. Do you think that could be a problem?
- Joined
- Sep 12, 2018
- Messages
- 1,501
- Reaction score
- 880
I never even considered it. Spray it, leave it for one minute and shake off excess. Such a small amount shouldn’t be a problem.
If you shake off the excess, we're talking a few drops of Star San in gallons of wine. It's not enough to have any effect on the measurement.
Thanks!
