What causes glassy potatoes please?

We thought we would have a go at growing an old heirloom variety of potato. They yielded a good crop despite the climate extremes we experienced over the last few months, however there are quite a few that are hard, glassy and yuck when cooked. It is the first time I have grown spuds, so what did I do wrong?, and how can I correct the problem for future reference. These were purchased as seed potatoes. Any tips, advice would be wonderfully appreciated. Thank you.

Maybe Not enough water, also temperature extremes.
It means that the starch in the potato has become sugar, you can find recipes for glassy potatoes.
I have grown them and I think they were gross

Tuber formation is characterised by both longitudinal growth and diametric growth of the stolon; stopping its elongation appears essential to the enlarging of the tuberising end. The balance depends on environmental conditions: long days and high temperatures favour the development of foliage and the elongation of stolons, whereas short days and low temperatures activate tuber formation.



In a temperate climate, in periods of active vegetation, this balance is obtained after a long time: there is simultaneous growth and tuber formation, with the latter gradually becoming predominant.



If conditions are not favourable to tuberisation, chiefly a temperature above 25°C, it stops. The stolons elongate, branch out and, sometimes, are transformed into aerial stems. The tubers resume their growth and become deformed.



In cooler conditions (overcast weather, rain, excessive irrigation), new tubers form along the stolons, stopping the development of the initial tubers that have already formed.



Glassiness generally occurs when the leaves turn yellow after haulm destruction. This phenomenon is explained by the fact that in the active vegetation phase, the young tubers are supplied with carbohydrates by the aerial parts of the plant. When the foliage is no longer functional, the second generation tubers draw sugars from the oldest tubers, whose starch is hydrolysed and their specific weight reduced. A similar phenomenon can be observed in some deformed tubers in which starch is translocated to the rose-end area from the heel-end (“glassy end”).

http://ephytia.inra.fr/en/C/21120/Potato-Secondary-growth-deformed-and-glassy-tubers

Mamaang, what variety did you grow?

Now and then the seed spud stays whole and they are rather glassy looking and would be horrible if cooked, its just possible if this was the first time you have growm them you may have used a seed one which was still on the plant.

They are the Robyn Adair variety, pink skins/white flesh, from what I understand dating back to the 1920's-1930's. Really good croppers though, we were quite surprised at what we did dig up for 12 seed potatoes. The good spuds are really nice to eat, but the glassy one's, not palatable! . I would be more than happy to grow them again, just needed to understand more about the how's and why's and to learn more about why this has happened.

Thanks heaps for the enlightening info, now I understand the reasons why so much more clearly and I really appreciate the replies. I have learned alot.

Lythande1.
I feel as if I need to be an Encylopaedia Brittannica, to be able to read and understand your post.
All one needs to do to grow good spuds, is good soil, and regular watering, especially during the formation of the tubers.

I think Lythande1 does a good job of researching subjects. 'she' saves others from doing the same research, and read the posts with interest