Cleaning Glass Carboys

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Hi Forumites,

Many reasonable suggestions here.

Remember that cleaning and sterilising are two different tasks.

CLEANING
In my experience, the best way to clean glass / metal tanks / carboys is with an Alkali cleaner @ 1 - 2% (by weight), preceded by a rinse to get the loose junk out.
Some folks like "built" alkali cleaners such as PBW, but I just use plain old Lye / NaOH / Caustic Soda. Wear gloves & Glasses.

Important to make sure to get the CO2 out of the container, as any CO2 will bind to the OH and produce Carbonate. This still cleans, but much less effectively. Leaving the carboy upside down in a milk crate for an hour does a good job of this.

Basic cleaning theory is that these four items are the contributing factor to cleaning:
  • Detergent Concentration
  • Time
  • Temperature
  • Impingement / Mechanical Action
An increase on one of the points above, means less of a need to rely on the others.

In a home setting, it's unlikely / unsafe to achieve high temperatures. Mechanical Action (scrubbing) is not the way I like to spend my time, so I rely on Time + Detergent Concentration. An easy, easy way to do this is to make up 2 litres of warm water, with 1% NaOH (lye): 20g and add it to the rinsed carboy. Stick a #7 solid bung in it and slosh around for 20 seconds. Then leave the carboy to sit for 10min with the liquid in contact with the soil. Move to a new spot of soil after a bit, etc.

You can reduce to 0.5% Caustic if you add Chlorine (bleach) to make 500ppm. If cleaning steel, make sure to be above pH of 13 to avoid corrosion.

Rinse a couple of times and you are good to go.

Caustic solution CAN be stored for reuse. It does deteriorate over time from atmospheric CO2 and from inactivation from soil.

STERILISING
Remember that in order to sterilise a surface, it must first be clean. Sterilising solutions cannot generally penetrate soils and so do not effective sterilise dirty surfaces.
For Sterilising, Star-San and others are great. Some of them foam-up, and that drives me nuts. I just go cheap and easy with a no-rinse Chlorine solution. You need between 50ppm and 200ppm for no-rinse. Normal bleach is between 5 and 6.5% Chlorine, so a 1:1000 dilution will give you a 50ppm to 65ppm solution. This is 1mL per Litre of water. You can double the Chlorine dose safely, if you're nervous. Remember that contact time is important: 2 full minutes submerged.

If your water is hard / has a high pH, you can increase the effectiveness of the Chlorine by adding 1/2mL of household vinegar (5% acetic acid) per Litre TO THE WATER to reduce the pH slightly. If you do this, make sure not to drop the pH below 6.0 as Chlorine gas can start to form below that level. Note never to add the Acetic Acid directly to the Chlorine as you WILL produce a dangerous cloud of Chlorine gas.

Also note that a slightly warm (chlorine) solution is significantly more effective than a cold solution, but the chlorine will dissapate somewhat more quickly.

In regards to scratches; steel tanks have a very specific polish grade that is required, in order to prevent soil adhesion, as well as ensuring that the surface can be properly "wetted". If there are scratches, or the wrong polish grade is used, the surface tension of water causes microscopic bridging of the scratches / peaks & valleys, preventing the sanitiser (or detergent) from contact with the surface. If plastic equipment gets scratched, throw it away. HDPE pails are cheap and available at any hardware store. If it says HDPE and it's white, it's Food Safe.
 
For wine making purposes, solutions of chlorine generally wouldn't be recommended. Contamination of the work area, even floors and drains etc., with chlorine containing agents increases the risk of TCA taint. It is better to stay with non-chlorinated sanitizers and cleaning agents, full steriliziation is not necessary for wine.
 
Stickman, Great point about TCA. Definitely an issue when using very strong Chlorine solutions, and potentially not rinsing or draining properly. Not an issue however with <200ppm and drained. Also related is the Cholrophenol issue, but again, not a problem at <200ppm. Agree that Chlorine for general housekeeping is also not great.

I would disagree with you on sterilisation not being needed, but I go very light on Sulphite use. As well, tap water as a final rinse for vessels can be tricky, as some municipal water supplies are not sterile. But I imagine you have success with your methods, so to each their own!
 
1) This is essentially a dead conversation. Read for info but if you want to ask a question or have a comment about cleaning - Start a new thread. You can paste a reference to this thread but start a new one. Wading back through the old comments is not something anyone wants to do unless they need to glean some info from it.

Show some initiative and start a new thread - You are far more likely to get responses that way.


That goes against so many things I’ve read on forum for years. Example:

NEW THREAD—-
What’s you’re favorite type bung?

Replies: That same question has been answered a million times. Search for it in the search engine. Don’t start a new thread!
 
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