While reading Busman's honeymoon I have come across the following sentence said by Mrs. Ruddle who is a country woman of some sort (seems like she works as an occasional housekeeper) while she explains why her son should bring sugar:
"So you might Bert," agreed his mother. "My Bert's got a wonderful 'ead. So you might. And a bit o' kindling' with it. You can cut across the back way -- and, 'ere, Bert -- jest shet that cellar door as you goes by-- sech a perishin' draught as it do send up. And, Bert, I declare if I ain't forgot the sugar -- you'll find a packet in the cupboard you could put in your pocket. There'll be tea in the kitchen, but Mr. Noakes never took no sugar, only the gran, and that ain't right for 'er ladyship."
The context here is that Lord and Lady Peter Wimsey arrive at a house they bought (through an agent) from a Mr. Noakes who should have been handing it over to them (or at least had it prepared for them). They find the house locked and no one seems to know anything about a sale Mrs. Ruddle is a local woman from (I'm guessing a bit here) a house nearby that seems to have worked at least partially as Mr. Noakes's housekeeper. After some initial confusion and a trip to a village close-by a key to the house is found and Mrs. Ruddle proceeds to show them around the house. They point out there is no coal in the house and her son Bert proposes he could fetch some from home.
What does gran mean in this sentence? The usual meanings of grandmother or a phonetic spelling for grand as Mrs. Ruddle might say it, don't seem to make sense so I'm assuming it's either a respelling of some other word or possibly an allusion to some product?