In gathering any apples left hanging, that might be useful for cooking. We found 2 apples that were very dirty looking, but very heavy. We assumed they were going to be hard and good for cooking. They were added to all the others from different trees and taken home.
It was only whilst preparing them for cooking that the first apple was thrown away. The 2nd apple was checked out in greater depth, and it was found to have Water Core for all of the flesh. This is why it weighed heavy, it was just water.
Unfortuneatly we did not note the variety, so it will have to wait till next year.
What is water core – An extract from https://www.yara.co.uk/crop-nutrition/apples/reducing-water-core-occurrence-in-apples/ says the following.
Water core develops in mature apples when the sugar sorbitol is translocated into the fruit faster than it can be assimilated. The area surrounding the core becomes water-soaked or translucent and may appear glassy and hard…..Inadequate supply of calcium is a major contributing factor.