Keep quiet about our old lady's whiskey (4,4)

I believe the answer is:

sour mash

'whiskey' is the definition.

'keep quiet about our old lady's' is the wordplay.
'keep quiet' becomes 'sh' (as in shushing someone).
'about' means one lot of letters goes inside another.
'old lady's' becomes 'ma's' (both can mean mother).
'our'+'mas'='ourmas'
'sh' going around 'ourmas' is 'SOUR MASH'.

I've seen this clue in The Telegraph.

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