K-Meta sanitizing question

[Trubador]

I have always used Iodophor for sanitzing buckets, bottles, hoses, etc for beer brewing equipment and recently wine equipment.

I see that some people are using K-meta in spray bottles for spoons, and miscellaneous items. (3 tablespoons per gallon of water)

I have a general question concerning K-metabisulfite as a sanitizer. If I make up a solution of it and put an item in to be sanitized, what length of time must the item remain in the solution and does it require air drying or rinsing with cold water afterward?

Thanks,
Jorma

 

[BrianD]

The consensus here, I believe, is two minutes of contact time for sanitizing. I don't think it requires air drying, as K Meta is used when racking to help prevent oxidation, and you soak corks in it when bottling. Still, some don't like rinsing with tap water because of a fear of introducing something back onto the santized surface.

I am confused by the various concentrations recommended for sanitizing. Per the container, two ounces per gallon. Per the last discussion here, 3 tbsp per gallon. I believe those are the same amounts. But then I see sites like this one (and others):

http://www.weekendbrewer.com/sanitizing_for_wine.htm

....where they state much lower concentrations for sanitizing...at least at some steps along the way. In this case, 1/3 teaspoon for 2.5 gallons of water for sanitizing bottles and corks! It's confusing.


Brian

EDIT: I've also seen reference to the winemaking faq at the old USENET group calling for 1 tbsp per gallon, and also some people that say they use a heaping teaspoon per gallon. While I don't think you can go wrong with 3 tbsp per gallon, it does make me wonder if you can do OK with less.

Edited by: BrianD

 

[Wade E]

I go by what it says on the bag as thats what counts in my opinion!

 

[PeterZ]

Trubador,

Iodophor is a true sanitizer, being an iodine compound. To legally be called a hard surface sanitizer a product must, at label dilution rates, kill 99.99% of all bacteria (5-log reduction) with a 60 second contact time.

It becomes a question of what you really need. My process is to keep everything scrupulously clean. When I transfer from a primary to a secondary the first thing I do after fitting the airlick is to wash the primary. Many things, including used wine bottles, go through the dishwasher.

The sulfites do two things. They produce SO2 gas under acidic conditions. This does kill bacteria. They also react with dissolved oxygen in the wine/must to inhibit the growth of aerobic bacteria (bacteria that must have O2 to grow, metabolize, and reproduce). Most of the bacteria thata can hurt our wine are aerobic (like Acetobacter sp. - the bacteria that converts wine to vinegar), and the sulfite solution puts them in a coma. Eventually (after hours) they die from old age.

There is one class of bacteria that we need to worry about when using Na- or K-meta as a "sanitizer: - Desulfovibrio sp. This bacteria uses the SO4 that results from the reaction of O2 with SO3 for its oxygen needs. It reduces the SO4-- to S--, which then becomes H2S - rotten egg smell. Fortunately, this bacteria does not exist in municipal water, as the chlorination kills it. If you are on well water that has a little odor, however, use bottled water. If you have a charcoal filter to remove this smell from your water, use bottled water. The charcoal will remove the H2S, but it will not kill the bacteria that produced it.

The net result is that you cannot go wrong using the iodophor first, followed by the K-meta. You should, however, always use the K-meta, as you always want a reducing environment after you have pitched the yeast.

 

[Wade E]

Peter Ive heard that a standard dishwasher does not sanitize as it does
not get hot enough, only a commercial dishwasher does. Is this true. I
do not use a dishwasher as like you I clean immedietly after using with
B-brite and then use K-meta before using again. Is the standard disher
a sanitizer?

 

[PolishWineP]

Some home dishwashers, like ours, have water heaters in them. Commercial dishwashers I think have to reach 180F in their rinse cycle. Most of them now days have rinse water booster heaters to ensure that is happening.
Peter, did I read right that you basically use your dishwasher in the world of wine just for washing dirty bottles?

 

[Trubador]

Trubador,


The net result is that you cannot
go wrong using the iodophor first, followed by the K-meta. You
should, however, always use the K-meta, as you always want a reducing
environment after you have pitched the yeast.

When I pitch ale yeasts in my beer, I always try to introduce as much
oxygen as possible. Is wine yeast different? You are saying
that i should have a reducing environment even on the initial pitching
of the yeast? This is a major difference from what I have been
doing.

 

[masta]

Wine yeast is no different than beer yeast in the fact that it needs oxygen for it's aerobic fermentation stage where a large colony of healthy yeast can grow for a complete fermentation when you transfer to a secondary carboy and put it under an airlock for the anaerobic stage.


The proper sulfite level helps kill and prevent growth of any bacteria during this fermentationstage while allowing the yeast to do it's work of converting sugar to ethanol and CO2.


If you are a successful beer maker than your sanitation techniques are certainly good enough for making wine since you have the added protection of sulfite.<O></O>

 

[PeterZ]

The yeast need oxygen to reproduce. While busy reproducing, the yeast is not expending much energy converting sugar to alcohol. All living things respond to their environment. When the oxygen level drops, the yeast turn to other sources of chemical energy. For yeast, that is converting sugar into alcohol.

I suspect that one factor in how vigorus the fermentation is is the amount of O2 in the must. If there is a lot, then the yeast will spend more time reproducing, resulting in more yeast cells. Once the O2 level drops, the yeast turns to conversion, and because there are a lot of cells, it really cooks.

The only real difference between wine and beer is that the source of sugar/flavor/character is different. Beer uses grains, which do not oxidize easily. Wine uses fruit, which oxidized more easily. (Notice how many fruits brown in a couple of hours? How long does it take wheat, oats, barley, etc. to go bad on the shelf?) Oxidation of must has the same negative effect on wine as oxidation of the wine itself. That's why we don't go too crazy with inroducing air into the must.

It's not the yeast, its the base that dictates how much air is good.

 

[Coaster]

I use my dishwasher on my used bottles (after soak and scrub). It has a disinfectant cycle that will melt plastic on the top or bottom shelf.

 

[Trubador]

The only real difference between wine and beer is that the source of sugar/flavor/character is different. Beer uses grains, which do not oxidize easily. Wine uses fruit, which oxidized more easily. (Notice how many fruits brown in a couple of hours? How long does it take wheat, oats, barley, etc. to go bad on the shelf?) Oxidation of must has the same negative effect on wine as oxidation of the wine itself. That's why we don't go too crazy with inroducing air into the must.

It's not the yeast, its the base that dictates how much air is good.

Makes perfect sense. I understand. This begs the question for me though. For beer, I stir very vigorously prior to adding yeast.


For wine, should Istir just enough to homogenize the must/water mixture prior to pitching the yeast? Thus not really introducing very much oxygen.


Also, I understand you said I can not go wrong sanitizning w/both iodophor and k-meta, but that would get expensive. I would have to prepare to separate solutions each time and fill my buckets, carboys, etc... Should I just skip the iodophor?

 

[masta]

I also make plenty of beer in addition to wine and have alwaysstirred my must and wort the same amount with a drill mounted stirrer without any issues. Vigorous stirring with wine kits is important not just to add oxygen but so the viscous concentrate and water can be mixed properly.

If you clean your equipment well then sanitize using the K-meta or (Na-meta since it is much cheaper) you will be fine.