Expert: Spencer W Thomas - 11/12/2008

Question
i have a layer of white film on the top of my beer.
what type of contamination is this?

i was also wondering if there is a way to fix it..... because, i have heard rumors of being able to rescue contaminated beer by racking it from under the bacteria, heating it to 170 for 15 mins, and then adding a small amount of fresh malt and yeast.

any truth to this?

Answer
A film could be caused by a bacterial or wild yeast infection.  

As to "rescuing" the beer, "it depends."

The procedure basically pasteurizes the beer, killing most of the microorganisms in it (thus the requirement to add new yeast).  Pasteurizing will change the flavor of the beer, generally not for the better.  You might be willing to live with that.

However, if the beer flavor has already been affected, killing the offending organisms is not going to fix the flavor.

So, first, you need to taste what you have.  If it's gone sour, or has any other sort of "off" flavor (cabbagey or medicinal are two common spoilage flavors), you might as well dump it. (Unless you like sour beer...)  If the flavor has not been affected, you could just try bottling it as is, then keep it cold and drink it quickly.  The good news is that whatever is growing in the beer is almost certainly not hazardous, so the worst you're in for is "yucky" tasting beer.