[NOTE: This question was asked in another forum recently and links were made to BIABrewer.info. alymere and a few others are doing a great job on that other forum in this thread. I hope this helps...]

As mentioned in this BIABrewer post, the answer to the question is yes.

Like anything that involves the word, "efficiency", things can get complicated very quickly so the following answer is hopefully a good simplification.

Imagine if my standard of "efficiency", just to be silly, was to soak 1 kilo of grain in 2 litres of water for 5 minutes and that we called the result of my "laboratory" test 100%.

Obviously, I could do two things straight away to get better results than the 100% "laboratory" test. I could soak the grain for longer or I could use more water.

The real laboratory brewing standards are quite high but they are not perfection so, while it is theoretically possible to get kettle efficiencies higher than 100%, it is unlikely/rare for home brewers except at very low gravity beers.

There is one further problem if my memory serves me correctly... Different countries have different levels of measurement (laboratory tests). Please feel free to use this thread to specify the laboratory tests of grain yield used in the US, UK and Europe.


PP