can you smell infections?

[tchuklobrau]

Well to start off i do not think i have anything wrong with my beer. This recipe i just made is a belgian dubbel with alot of red currant pulp added to the primary(the juice will go in the secondary). While i was careful and boiled the berries before adding them, the chance of infection is always there.
After only a 4 hour lag(loving making starters) i have airlock activity. While all smells like a belgian2x( yes im an airlock sniffer), i was just wondering if bacteria would give it a different odor while fermenting?

 

[lostboysbrew]

Not likely, unless it was a really bad infection. You wont get an infection in yeast that quickly. It sounds like everything that went in was clean, you should be fine. Not to mention, the offgassing of fermentation has different smells based on the yeast....

 

[samc]

Vinegar or sulfur can be a smell that is telling you infection is present. I'm sure other infections have an odor as well. You could probably train your dog to sniff them out, if you were really into such a thing.

 

[Tiber_Brew]

Vinegar or sulfur can be a smell that is telling you infection is present. I'm sure other infections have an odor as well. You could probably train your dog to sniff them out, if you were really into such a thing.

Just a note about your sulfur comment... don't some yeasts give off a sulfur smell during healthy anaerobic fermentation? I've brewed several beers (ales and lagers) that gave off a sulfur smell that weren't infected, and the yeast cleaned up the sulfur quite nicely. In other words, a sulfur smell might not necessarily mean you have an infection.

To the OP, I have been able to smell a bad phenolic infection in a beer, but it was after primary fermentation. The taste pretty much confirmed my nose's suspicion, too.

TB

 

[Revvy]

Vinegar or sulfur can be a smell that is telling you infection is present. .

Not really because sulphur smells can also simply be a product of the yeast, (think Rhino Farts) especially lager yeasts (which is why we lager anyway.)

And a lot of new brewers panic and think the slightly sour smell of co2 is "vinegar" or and infection.

So neither are good clues as to whether it's an infection or not. More times than often it's new brewer panic and not an infection.

And even phenolic smells can only be a byproduct of fermentation, and not necessarily something that is going to stick around after carbing and conditioning.

tchuklobrau, the thing to realize is that fermentation is often ugly and stinky and that is in perfectly NORMAL beers.....It's really hard to ruin your beers, so I find that jumping at every look and smell that doesn't look right and assume it's infected is really counterproductive.

Read this, Revvy's advice for the new brewer in terms of infection worry.

 

[tchuklobrau]

Oh sorry the point was missed. The fermentation smells wonderful just like a belgian dubbel should. That just made me wonder if it would be possible to smell an infection or if it would be to difficult to tell apart from normal fermentation.

 

[ReefkprZ]

I had one horribly infected batch, and honestly I could not smell it during the fermentation, I could only slightly smell it at bottling and the beer only tasted slightly funky but drinkable at that time, after several weeks in the bottle it had gone straight vinegar, and there was no mistaking the acetic acid wafting up out of a freshly poured glass. and the taste was ungodly horrible, red cooking vinegar anyone?

 

[tchuklobrau]

Knock on wood no infections to date.

 

[Dogphish]

HIJACK: does sulfur smell like eggs or corn? my yeast always smells like sweet corn.

 

[tchuklobrau]

sulfur smells like rotten eggs

 

[dmfa200]

I had an infection recently that smelled very fruity, like overly ripened grapes.
It actually smelled really good, but tasted sour.

I want to tell you what I did wrong to infect it.

When it came to cooling down my wort. I turned off the heat. Started the cooling water to my IC. Grabbed the same spoon I stirred my mash with and thought "This wort is still hot enough to kill those bacteria all over my spoon."
WRONG!

Lesson learned.

Let the ridicule begin.

 

[tchuklobrau]

If that smell is one that you are worried about there is a diy thread on here on how to make a filter to eliminate sulfur smells from your fermenter. I used it with my kolsch for fear of the wife killing me if i stunk up her closet. worked like a charm and only cost $9 to make.