I had a tin of golden syrup for a long time - longer than I care to admit. When I opened it up yesterday (to sweeten up some mulled wine), it was granular (a bit like honey can be), and black around the edges.

Is this 'bad', or just different?

Is the blackness the result of some chemical reaction with the tin?

And in general, does it eventually go off, or does it last indefinitely?

  • 2
    The black stuff is most likely the crystallised minerals from the sugar. It's normal, and occurs more often if you let the contents dry out
    – TFD
    Dec 7, 2010 at 8:31

5 Answers 5


Golden Syrup improves with age according to Heston Blumenthal's "In Search of Perfection". Here he analyses a 70 year old glass jar of Tate and Lyle Gold in the lab finding that the "older treacle contained the same flavour compounds as the normal stuff, but each was intensified".

In his recipe he fakes the ageing process by baking the tin at 70ºC (158ºF) for 24 hours noting that the flavour will continue to improve up to 100 hours.

  • +1 That validates my point that it does not go off. Also, very interesting, as I always heat my tins in the oven before use with the lid ajar, so that the syrup becomes more fluid for ease of use. Might inadvertently improve the end result!
    – Orbling
    Dec 8, 2010 at 0:42

My favorite saying is When in doubt throw it out. Having said that you should throw that away. The black can either be from the oxidization of the tin or it could be mold growth. In either case golden syrup only has a shelf life of about two years; or one year after being opened, and it should be refrigerated after opening. The granulation could be fixed by reheating but the black is not worth the risk.

  • 1
    Black around the edges makes me wary, too. Granulation is normal. Dec 6, 2010 at 18:52
  • 3
    The black stuff is unlikely to be bacteria, as the extremely high sugar content is pretty antibacterial (the sugar tends to dry out the little beasties). It is susceptible to mold, however, so I'd still think you'd want to pitch it if it's discolored.
    – bikeboy389
    Dec 6, 2010 at 21:43
  • 1
    Well, it's all gone now, some in the bin, and some in the mulled wine. No untoward symptoms as yet :)
    – Benjol
    Dec 7, 2010 at 5:41
  • 2
    -1 NEVER refrigerate sugar products. They are perfectly persevered in...ummm...sugar. They have exceptionally long shelf lives if keep in a cool pantry, like tens of years!
    – TFD
    Dec 7, 2010 at 8:29
  • 1
    Just wanted to add a bit of information: lylesgoldensyrup.com/faq.php The FAQ says not to use past the "Best Before" date.
    – Varuuknahl
    Dec 7, 2010 at 16:25

Golden Syrup pretty much does not go off. It is a blend of sugars and preserves as well, it should keep for many years. It will crystallise slightly over time though that can usually be solved via warming.

Bacteria is highly unlikely, mould can form on it - that would be a reason to chuck it out, possibly not all of it. The only serious issue is from the tin itself corroding, which is what the black area could be. I've known households to use that stuff from a 20 year old tin and have no issues whatsoever. It definitely does not need refrigerating any more than sugar does.

  • Unless you know someone is allergic to mold, it's usually safe just to scrape the mold off the top, and then clean the container. This happens with maple syrup from time to time. Nov 24, 2011 at 21:38
  • @Chris Cudmore: Aye, quite true. I am allergic to mould myself, so am the special case. But even I occasionally do such things if very careful.
    – Orbling
    Nov 25, 2011 at 14:49

I've just thrown away an open tin of the syrup, as I thought it had a funny aftertaste. Still within the sell by, but open for about a year.


Sweetheart, if you have doubts- just chuck it! It's not worth a couple bucks to eat something that you think will could make you sick full stop.


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