Do infections always drop the SG?

I have a Belgian and, well, it's funky. I can definitely imagine it getting better with age and some chilling. I can also imagine it going very very south. Needless to say, I'm not tossing it yet. However, it has the same taste of the other few infected batches I've had. On the other hand, it's not all that bad... yet. And the S.G. is right at 1.010 which is right in the ball park of what I've come to expect (I routinely beat the attenuation estimates as a result of using pure O2 aeration).

I know, of course, that if it's not infected it's going to get better with age. I also know that it's too early to tell. I am thoroughly RDWHAHBing.

But I was just wondering whether S.G. is a good way of predicting infection. Does an infection always lower the SG?

Nobody has an answer, eh?

I don't see how an infection could NOT impact the gravity. Infections by definition are wild yeast or bacteria consuming whatever sugars were left over. Now, if the infection was mild or new, there might not have been enough time for the gravity reading to have been impacted much.

But, that's just a guess.

A few days later, no further drop in SG. On the other hand, infections can take a long time to eat through sugars- wild infections aren't the lean mean purebred sugar-eatin' machines that beer yeast is.

More significant (always) though is the fact that the taste is starting to improve. The bad licking-a-skunk-ass flavor is going away. There are still bubbles on the surface, possibly indicative of krausen or infection, but the flavor is improving. Time to move to secondary, methinks.

Damn Squirrels said:

A few days later, no further drop in SG. On the other hand, infections can take a long time to eat through sugars- wild infections aren't the lean mean purebred sugar-eatin' machines that beer yeast is.

More significant (always) though is the fact that the taste is starting to improve. The bad licking-a-skunk-ass flavor is going away. There are still bubbles on the surface, possibly indicative of krausen or infection, but the flavor is improving. Time to move to secondary, methinks.

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If you used a wit yeast, you'll have krausen till the cows home home.

...and...how many is a "few" infections you mention you've had?

My guess is that maybe you've tossed a batch or two for being under suspicion.

Stay the course on this one. I'd bet it'll be a great beer.

What yeast did you use? My last Belgian Pale was / is a little funky as well. I used WLP 530. I had a previous thread on this as well. It tastes a little sour, but not too bad. I'm not sure if it is infection or what.

Damn Squirrels said:

But I was just wondering whether S.G. is a good way of predicting infection. Does an infection always lower the SG?

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S.G is not a good benchmark for predicting infection, you can have very low SG and still have a very clean beer.
However...
An infection will assuridly lower your S.G. Everything is getting chowed, and there's virtually nothing left over to ferment out.