Possible Clues:

• Confidence, sense of wellbeing
• In other words, in man it�s a state of mind
• It may need boosting
• Mostly extra beer causes spirit of optimism
• There's more about the spirit of a half-century
• U.S.O. shows boost it
• Degree of confidence the writer includes in speech
• Self-confidence Sir Thomas displayed crossing a lake
• Extra short on top of beer may give you confidence
• General level of confidence or optimism