Many sites suggest the brining time for a turkey should be one hour per 500 g, or 8-18 hours in total. Nigella says it can be left overnight or for up to two days. Is this correct?
Brines vary in salinity and you need to look at the concentration of salt. Nigella's brine is not particularly salty, which means that the brining time can be slightly longer. Also, larger birds tend to need longer brining as it can take longer for the brine to penetrate the meat. And most importantly, you need to be able to keep the bird in its salt-water bath cold during the brining process. So most people will brine the turkey for 12-24 hours due to space restrictions. However, for this particular brine it is fine if you have enough fridge space to allow the turkey to brine for up to 2 days.