Ask Dr. Potato

With 930 posts, chances are there's already an answer to your question. Please try searching below before submitting a question to Dr. Potato. Use multiple words to help narrow down the results. For example, search for "potatoes" and "group" if looking for an answer on cooking potatoes for large groups.

Back To Dr. Potato Home

Q&A: Re-conditioning Idaho® Potatoes


Someone told me that my potatoes have too much sugar in them and that is why they fry up dark.  They said I need to “re-condition” the potatoes.  Can you tell me what exactly this means and how long it takes?


All potatoes have starch and water, sometimes the starch is referred to as solids.  The starch in a potato will convert over to sugar if it is stored too cold.  A high solids potato, such as the Idaho Russet Burbank, will typically fry up golden brown.  However, even when you start with the best ingredients you need to be aware of the challenges of trying to do fries from scratch.  Potato processors even struggle for a consistent fry, and they have the ability to vary time and temperatures, as well as utilize processing efficiency for the final product.  In most areas, potatoes are harvested only once a year. Conditioning or re-conditioning potatoes refers to the procedure by which sugar in the potato can be lowered to a more acceptable level for making French Fries.  The normal recommended storage of fresh potatoes is at a temperature of 45-48°F.  Below 40°F, the starch converts to sugar.  When you elevate the temperature to 60-70°F the sugars begin to convert back to starch.

At the distributor or produce house, if you have a customer (or several) that does fresh fries on location, store these potatoes in a warmer climate.  At the very least, move the potatoes designated for frying down from the upper levels of the refrigerated room where the air is normally colder, place the potatoes at the entrance of the room where the clear plastic curtains hold in most of the cold but the constant entry and exit by people will make that part of the room a little warmer.  Place the potatoes out of the cold warehouse onto a covered dock (unless it is also chilled) to warm up for several days before shipping to your customers.

At the unit level, set aside an area for the potatoes and use the “First In First Out” method so that you use up the warmest potatoes first and the newly received potatoes might have 5-7 days before being cut into fries.  It will take a minimum of 5 days to make some headway towards reducing the sugars.
Here is one suggestion on how to determine if you have a problem: Use diabetic test strips, sometimes sold for urinalysis.  The best ones have a color code on the jar, with aqua showing less or no sugar and dark brown showing strong evidence of sugar.  Cut a raw potato, place the strip on it for a few seconds, and wait for it to turn color from the plain white to the aqua or dark brown. If it shows sugar, then plan on re-conditioning the potato (sometimes referred to as de-sugaring or de-sweetening).  If you can’t do this, at a minimum, when you cut the potato, rinse the slices in a plastic bucket with running water until the water runs clear, eliminating some of the excess starch and sugar.  Then blanch the potatoes before storing and finish frying.  Blanching…that’s still another chapter in the saga of successfully making your fresh Idaho potatoes into beautiful French fries.