Taking an sg reading

[zx7rtas]

Is it at all possible to contaminate the brew when taking an sg reading as air either enters through the air lock

[chadjaja]

You will be right. I and others put sterilisation solution in the air lock rather than just water as any that is drawn in the fermenter is sterile and any bugs etc are retarded from growing inside it.

If you pour from your tap in a few stages you can pour and not suck water from the air lock back in and there is no danger from the bubbling action either.

[warra48]

Your beer will have a blanket of CO2 on top.

The tiny bit of air drawn in will soon enough be replaced by more CO2 coming out of solution.

Never yet heard of an infection caused by drawing samples.