Will bromine/chlorine permeate plastic bucket?

[brewzombie]

I just built a water bath to control fermentation. I use plastic buckets as primary fermentors (with the usual airlock) and sit them in a temperature controlled cooler. I recently added bromine to the water (which you would normally add to hot-tubs) to prevent microbial growth in the water (others had suggested chlorine, but bromine seemed less smelly and more stable/easier). Now I'm wondering if the bromine (or chlorine as an alternative) would permeate through the plastic buckets and get into the beer. They sit in the water bath for a month before bottling. I haven't actually used the water bath but intend to do so tomorrow and am starting to think I should just drain it and forgo the bromine. Any educated thoughts?

 

[drkwoods]

I doubt that could get through plastic, especially at the concentration level needed to sanitize that water. Make sure you keep the ppm concentration very low.. Bromine is very effective even at low levels. Keep the odor from the top of you brew bucket you wouldnt want it getting in there either..

 

[brewzombie]

I doubt that could get through plastic, especially at the concentration level needed to sanitize that water. Make sure you keep the ppm concentration very low.. Bromine is very effective even at low levels. Keep the odor from the top of you brew bucket you wouldnt want it getting in there either..

The water level is well below the lid of the brew bucket.

Here's some more info:

The chemical in the sanitizer is 1-bromo-3-chloro-5,5-dimethyl-hydantoin. Bromine and chlorine are released in water (according to the MSDS), so all 3 chemicals are free in solution and maybe gas phase too. I've added 1 x 20 g tablet to the water (80 L max) and it's dissolved a little over the last few days, but not much. I can barely smell anything, but it is detectable. I don't know what the proper concentration to use is or if I'm below (maybe) or above it (unlikely).

 

[brewzombie]

The plastic bucket is Food Grade HDPE (High Density Polyethylene).

One website said this plastic had: "Limited resistance (moderate attack and suitable for short term use only) to Halogenated Hydrocarbons and Oxidizing Agents" [http://www.dynalabcorp.com/technical_info_hd_polyethylene.asp]

Another site listed bromine and chlorine among chemicals that have little to some effect on the plastic, but these were not listed as unrecommended for continual use [http://pt.rexnord.com/products/guards/orange_peel_guards/hdpechemresistpdf01feb.pdf]

My thinking now (but still nervous) is that even if permeable, the bucket won't let any chemicals into the beer without noticeable damage to the outside of the bucket. It won't just pass through invisibly. Any chemists know anything about this?

 

[JuanMoore]

I don't think it will penetrate, but if you're worried about it you could use star-san instead. It will prevent microbials and is known to be completely safe for the beer (and humans).

 

[rosier9]

yes (I think) it will penetrate the brewing bucket, no at a level (and time constraint) of normal brewing... don't worry about it... however I am curious to see what you have going on here, mostly temperature control... as for the post about damage being visible to the bucket, I (not a chemist) would doubt that any damage to the bucket would be visible to the human eye... i.e. molecular

 

[Bottenbrew]

If it goes through it would just permeate and you wouldn't be able to see anything. I think a plastic bucket would be thick enough, but there is a reason chemistry labs use glass, plastic is permeable.

 

[brewzombie]

Thanks for your advice everyone. In the end, I decided to play it safe and used fresh water without any preservatives. I'll probably add starsan if (when) the water gets smelly or just replace the water (if it doesn't happen too frequently). If the cooler was big enough, I could have used glass carboys and avoided this concern. Didn't think of it when I designed it. Pretty much the biggest cooler I could find anyway.

I'm happy to report that the water bath system I made works perfectly. The temperature was set to 19 C and hasn't budged even during vigorous primary fermentation.

 

[Bottenbrew]

Good stuff, glad it is working out.