For the second year running my maincrop potatoes (Maris Piper this year, Desiree last year) have produced an abundant crop. However when boiling it seems that all is well at first then suddenly they just disintegrate and turn to slop in seconds. Apparently we've had a wet summer but not here in Sheffield, so i have had to give them a good soaking a few times. Appearance wise they look fine and are good for baking and ok for chips (albeit very dry). This is the second year on my allotment which still has fairly poor soil (dry and a bit silty) so i was wondering if this is the problem. I have grown Desiree in the past in very clay soil with no problems at all. Some of the other allotment holders have had similar problems, though some were ok. Just wondering really if the problem is the soil or maybe lack of water. For some reason there were no flowers (or very few).....is this a symptom of something???
I found this on the webternet:
Do-it-yourself Specific Gravity Test for Potatoes
Add 225gm table salt to 1775 gm water and stir until dissolved. The temperature should be around 20C. This produces a salt solution with a specific gravity of about 1.080.
Place the potatoes into the solution, one at a time. If they float, they will be good, firm boilers. If they sink, they will probably be mealy when boiled. These are high dry matter potatoes, and probably best steamed.
is this a symptom of something???
It's just a symptom of boiling them too long. As Debbie says, some varieties just do that. Maris Piper make good chips but they only need a short boil or they disintegrate as you've discovered. The great thing about growing your own is that you can try dozens of different varieties that 'shoppers' never get to experience. Trouble is you have to treat them all differently :(
Some potatoes just do that - Edzell Blue are notorious.
Home grown spuds need shorter cooking times than supermarket ones. I was brought up with the rule of thumb that potatoes need 15 minutes. I boil our current crop for 8 mins max.
Cook by adding cold water and heating rather than adding boiling water. There is a zone between 50 and 70 degrees C in which an enzyme is activated which alters the cell structure. (Calcium ions and pectins cross link cells making them more resilient at higher temperatures). "Persistent firmness" can be encouraged by preheating to the zone for 20 to 30 minutes before bringing to the boil. Got to admit I've never gone to that length to test the theory, but your spuds will spend more time in the zone if you heat them in cold not hot water!
Your problems sound like an exact replica of mine - no flowers, potatoes dry, foliage dying back prematurely. I have always grown Desiree usually with excellent results - not this year. I am sure the dry weather had something to do with it. My total harvest has been abyssmal.
I find this happens to maincrop potatoes if I cook them very freshly dug; 3 weeks + later after being stored they are fine but they still need cooking for less time than you might expect, and straight into boiling water not from cold, then turn down immediately so the water is barely moving.