Silicon tubing question

[Honda88]

So a few days ago I brewed for the first time on my all grain setup and used my wort chiller that happens to have silicon tubing from 2 different manufacturers on it. After one run some of the tubing is stained and some of it isnt. Why would this happen? Are there some grades of silicon that dont stain? I'm puzzled.

 

[trevelynzx]

hot side/ cold side? my silicon tends to pick up some of the hop colors on the hot side. can reduce it with a hot pbw soak if it really bothers you but functionally it should be fine.

 

[Honda88]

it doesn't bother me that much I was just wondering why it would happen. I am very confident is has nothing to do with temps. Its just strange to me and makes me question the quality of the hoses.

 

[ong]

If it’s on the “output” side, I’d imagine it had to do with hot water passing through your copper tubing and picking up some oxides. If on the cold “input” side, maybe related to iron in your water?

 

[Vale71]

Silicone stains, there's nothing you can do about it. This happens with gaskets as well.

 

[Honda88]

All the tubes have copper before them so if it picked up something from the copper I would think they would all be discolored. Also none of the tubes used during mashing stained either. It was only the new tubing that I used to finish the wort chiller. I'm just amazed that brand new silicon would stain like this after one use.

 

[Vale71]

I get particularly bad staining when transferring very hot (>90°C) wort. The hose connecting the whirlpool to the plate exchanger is the most severely affected, I guess because of the combination of very high temperature and longer contact time. The ones I use to recirculate the mash (RIMS system) are mostly in pristine condition despite the very long contact time, so temperature does appear to be a primary factor.

 

[Smellyglove]

Temperature, SG, contact time, and quality of the hose. It just happens. But the rate at it happens at is related to the things I mentioned. Probably other factors as well, but these are the "simple" ones.

 

[Honda88]

I get particularly bad staining when transferring very hot (>90°C) wort. The hose connecting the whirlpool to the plate exchanger is the most severely affected, I guess because of the combination of very high temperature and longer contact time. The ones I use to recirculate the mash (RIMS system) are mostly in pristine condition despite the very long contact time, so temperature does appear to be a primary factor.

I use the same hoses for cooling as I do for mashing so they are also exposed to the high heat. I noticed the new tubing seems to have s rougher surface so maybe it is trapping more coloring from the wort than the other tubing. My main concern was that I had somehow got ripped off and the tubing I received wasn't 100% silicone. Since others have had staining problems I'll just assume it's the difference in the silicone..

 

[MaxStout]

I use the same hoses for cooling as I do for mashing so they are also exposed to the high heat. I noticed the new tubing seems to have s rougher surface so maybe it is trapping more coloring from the wort than the other tubing. My main concern was that I had somehow got ripped off and the tubing I received wasn't 100% silicone. Since others have had staining problems I'll just assume it's the difference in the silicone..

That's probably the best theory. The rougher tubing would be more prone to picking up minerals, etc., that would cause staining.