Can final gravity indicate infection?

[sweaterman]

I completed a recipe that you can see here: http://hopville.com/recipe/1279641/saison-recipes/midsummer-nights-dream-saison-v20-dme

I took great pains to sanitize. Soaked everything in PBW and Starsan. Yet my FG was 1002. Seems incredibly low. I kegged it anyway (also my first beer ever that I am kegging) and am doing the "set it and forget" method. Has anyone had experience with this? The predicted FG was 1014, seems unlikely that it would get down to 1002. I was hoping to bring this brew to a friend's house who just got done with a round of med school finals.

 

[djfriesen]

Well, it's possible. That does seem pretty low for that recipe. Best way to know is to pull a sample and taste it. Did you look at it or smell anything funny coming out of fermenter? I haven't used candi sugar in a beer that small, so I don't know how it would affect it, dryness wise. Taste will be the best indicator at this point.

 

[sweaterman]

And how would it taste if infected? Sour? Or does it depend on what it is infected with?

 

[djfriesen]

And how would it taste if infected? Sour? Or does it depend on what it is infected with?

Depends on what it's infected with. If you have acetobacter, it will taste like vinegar. Lactobacillus lends a sour taste, akin to sour milk. There are other infections, and they all lend a slightly different character. Some can results in good beers, others can only be dumped.

 

[sweaterman]

I haven't used candi sugar in a beer that small, so I don't know how it would affect it, dryness wise.

Finally, could the candi sugar drag down the FG like this? I thought it would only only increase the OG.

 

[chumpsteak]

what were your ferm temps? I had a couple of my early AG beers attenuate super low like that when I underpitched with too high ferm temps. When yeast are stressed they do crazy things. Infection by bacteria or wild yeast is possible, but if you were careful with sanitation it's not likely.

 

[sweaterman]

I fermed really hot because it is a saison and used a saison yeast. Above 78F (I have a temp strip on the side of the fermenter), using a brewbelt.

 

[djfriesen]

Well highly fermentable sugar boosts OG, but it is also likely to dry your beer. It appears it's only around 78% fermentable, which seems like it wouldn't dry it out too much.

I would guess chumpsteak got it right, especially since he has had it happen and in the absence of typical symptoms of infection.

 

[chickypad]

Finally, could the candi sugar drag down the FG like this? I thought it would only only increase the OG.

Candi sugar (mixture of fructose and glucose) will absolutely bring the FG down and dry the beer out, just like plain dextrose and sucrose will. They are pretty much 100% fermentable. That is the purpose for using it in styles like this.

 

[sweaterman]

Alright guys, thanks for the quick info. I will ride this one out and taste it on Thursday and Friday just to see how it is. Hopefully it will be good and ready for that party on Saturday.