small beer 
noun [mass noun]
1British A thing that is considered unimportant: even with £10,000 to invest, you are still small beer for most stockbrokers...
- Describing himself as an ‘amateur hunter’, the lorry driver from Nottingham says baldly that breaking the law will be small beer for those determined to protect their right to chase and kill animals for fun.
- For one thing, however hard the Chancellor's advisers try to pretend that an increase of eight pounds a week is small beer for top earners, a hike of £400 in your tax bill is substantial for all but a few in Britain.
- The budget of some £400,000 a year looks like small beer compared with the purchasing power of the world's major institutions and leading collectors - the competition.
2 archaic Weak beer: flat beer is just as bad as small beer...
- His drinks cellar would have been stocked with vast quantities of strong beer and small beer (a weaker brew), as well as a range of wines such as claret and canary (a light, sweet wine from the Canaries).
- And some small beer in the mornings, for my digestion.