Keeping Vinegar (acetic acid) in a glass container with a tap and rubber gasket sealed glass lid?

[Erina]

I get five litre quantities of White Vinegar (5% Acetic acid) in HDPE (High Density Polyethylene) containers and have been assured their stability for up to one year. While this is comforting, it's also not an issue as I will go through that allowance in around a single months domestic use.

I would however, like to have a more practical management system and am looking into using a drinks dispenser: http://www.kilnerjar.co.uk/index.php/kilner-range/drinking.html?p=1

This container is mostly comprised of glass, and in a size that I can keep everything in one place, as now. With a tap at the bottom I avoid miss-pouring from the spout of the plastic container as oxygen passes through too rapidly and the flow becomes unpredictable, but that is a metal tap and is comes with silicone gaskets. Finally the top (natural/synthetic?) rubber gasket also concerns me, even if not in contact with the vinegar itself.

1. What affect over time will a constantly replenished, yet ever decreasing, concentration of 5% acetic acid have on a glass container? Will it erode the glass, or cause it to become unstable over time?

2. There are several after-market taps that are of a better quality to the one provided in the example product I offered, which come in both stainless steel and brass versions, all with very good reputations, they also require silicone gaskets and I wonder what the acid will do to these materials over time, given that conditions will mostly be standing, only at times passing solution?

3. I am unsure if the rubber seal used at the top (sandwiched beneath a thick glass lid) is natural or synthetic, but in both cases I wonder how the rubber would react to the fumes from the acid in the air trapped inside the jar? I have checked company literature and they don't mention anything of it, yet it's not designed for the purpose that I am interested in using it for, however there are plenty of chances that it will be used (for short periods) with lemon juice infused water.

 

Finally, the wildcard: I also plan to keep Apple Cider Vinegar (with Mother: cellulose substance made up of various Acetobacter bacteria) in a separate container, which has a similar acidity (but not as much as I understand it) but will be accessed a lot less frequently, lasting anything up to six months, but in an ever decreasing quantity of course.

 

Many thanks for the help!

[StringJunky]

Here's a chemical resistance chart for various types of rubber materials with acetic acid . you are looking for a rating of 1.

 

http://mykin.com/rubber-chemical-resistance-chart

Edited August 8, 2017 by StringJunky

[Erina]

Ah, thanks! Silicone looks to be standing up to it's reputation, that's good. But I'm unsure yet what type of rubber I am dealing with..

[StringJunky]

Their jars are used in pickling so i would think that top ring will be of similar material used in them. Ring them up and ask, the number's at the bottom. 

Here's some silicone ones; note the measurement. https://nutleyskitchengardens.co.uk/10-silicone-reusable-sealing-rings-for-clip-top-jars

Edit: if you look in that video in your link a lemon drink is dispensed so it must be quite acid-safe on all the materials  used in it. Everything, I guess, would be at least pickling material quality... that's what they do. 

Edited August 8, 2017 by StringJunky

[Erina]

I was actually waiting several days for an official email reply until taking you up on your advice and telephoning, to which I learned the rubber is made from a vulcanised synthetic food-grade material, and therefore likely robust against diluted acids (they couldn't tell me exactly what it was though). The lady did highlight that the containers were not designed as a storage medium, rather for dispensing, and so I would be using them for an alternative purpose to what they were designed for.

Since we last spoke I have it on assumed authority that outside of the scientific world it would only be hydrochloric acid that glass would have long term issues with, not likely a dilute 5% concentration of acetic acid. The company I was in contact with only mentioning the guarantee their supplier gave them regarding their glass containers, which was by no means a measure of their durability under the conditions I was interested in.

Further research yielded positive results regarding a 304 Stainless Steel tap (https://www.amazon.co.uk/dp/B06XPG2CLS?psc=1) rated by the BSSA (British Standard Steel Association) to conclude: "The 304 types are normally considered as suitable grades for most applications, including handling and storage", long term stationary storage is just what I need!

So I now feel that I have enough information to be confident enough to put the system together.

 

Many thanks!

Edited August 9, 2017 by Erina

[StringJunky]

45 minutes ago, Erina said:

I was actually waiting several days for an official email reply until taking you up on your advice and telephoning, to which I learned the rubber is made from a vulcanised synthetic food-grade material, and therefore likely robust against diluted acids (they couldn't tell me exactly what it was though). The lady did highlight that the containers were not designed as a storage medium, rather for dispensing, and so I would be using them for an alternative purpose to what they were designed for.

Since we last spoke I have it on assumed authority that outside of the scientific world it would only be hydrochloric acid that glass would have long term issues with, not likely a dilute 5% concentration of acetic acid. The company I was in contact with only mentioning the guarantee their supplier gave them regarding their glass containers, which was by no means a measure of their durability under the conditions I was interested in.

Further research yielded positive results regarding a 304 Stainless Steel tap (https://www.amazon.co.uk/dp/B06XPG2CLS?psc=1) rated by the BSSA (British Standard Steel Association) to conclude: "The 304 types are normally considered as suitable grades for most applications, including handling and storage", long term stationary storage is just what I need!

So I now feel that I have enough information to be confident enough to put the system together.

 

Many thanks!

You have done your research!  If the tap does discolour to an unacceptable degree in the long term seek out one made from 316L or 317L stainless steel which are even more corrosion resistant in ascending order. I think 304 will be fine though for your application. You could even check out plastic taps used for beer kegs if the need arises.

Edited August 9, 2017 by StringJunky