Spudding potatoes, also known as green potatoes, refer to potatoes that have been exposed to sunlight while growing. This exposure causes the potato tuber to produce chlorophyll, giving it a greenish tinge. While some claim that green potatoes are toxic and should be avoided, the safety of spudding potatoes is still up for debate.
Are green potatoes actually poisonous?
The green color in potatoes comes from increased levels of glycoalkaloids, specifically solanine and chaconine. Solanine is also found in other nightshade vegetables like eggplant and tomatoes. In very high concentrations, these glycoalkaloids can be toxic to humans. However, solanine levels in most green potatoes are not high enough to cause harm.
One study found solanine levels ranging from 5.9 to 18.8 mg/100 g in commercially grown green potatoes, compared to 2 to 13 mg/100 g in normal potatoes. While solanine is higher in green potatoes, levels are generally not high enough to cause poisoning when a normal serving is consumed. Even the 18.8 mg/100 g found is far below the estimated lethal dose of 3-6 g/kg body weight.
However, sprouts and severe greening in potatoes may indicate very high solanine content. One case study reported solanine toxicity after a man ate potatoes with pronounced sprouting and greening. People with gastrointestinal, liver or kidney conditions may also have more sensitivity to glycoalkaloids.
What are the risks and symptoms of solanine poisoning?
Mild or moderate glycoalkaloid poisoning can cause symptoms like:
- Nausea
- Vomiting
- Diarrhea
- Stomach cramps
Higher levels may cause more severe symptoms including:
- Headaches
- Fever
- Low blood pressure
- Confusion
- Delirium
- Hallucinations
- Paralysis
- Coma
Death has occurred in rare cases of very high doses, but this is almost always from intentional poisoning rather than accidental consumption.
How can you reduce solanine levels in green potatoes?
While solanine does not easily break down with cooking, green potatoes can be made safer in a few ways:
- Peeling – Most solanine is concentrated in the peel and just below the skin. Peeling may remove 70-90% of glycoalkaloids.
- Soaking – Soaking peeled and sliced potatoes in salt water or vinegar water can help leach out some solanine.
- Cooking methods – Boiling peeled potatoes in copious amounts of water that is discarded can help reduce glycoalkaloids.
Are commercially grown green potatoes safe?
Commercially grown potatoes undergo inspection and grading to ensure safety. Potatoes with high solanine levels or visible sprouting/greening are typically identified and discarded. This makes commercially grown green potatoes relatively safe compared to homegrown or dumpster-dived spuds.
However, it’s impossible to fully eliminate all green potatoes. Occasional light greening can happen even in commercial potatoes if growing conditions promoted chlorophyll production.
What are guidelines for safely eating green potatoes?
To enjoy spudding potatoes safely, follow these tips:
- Avoid potatoes with sprouts or pronounced green color.
- Moderate consumption of slight-medium green potatoes.
- Peel potatoes to remove most glycoalkaloids.
- Slice/dice potatoes and boil in plenty of water, discarding the water.
- Don’t let children or sensitive adults eat green potatoes.
With proper preparation, the small amount of solanine in most commercially grown green potatoes should not pose any serious risk. However, when in doubt, remember it’s better to be safe than sorry and discard heavily green potatoes.
Can you eat mashed potatoes made with green potatoes?
As long as the green potatoes are only slightly discolored with moderate chlorophyll production, mashed potatoes made from them should be safe to eat after peeling and proper cooking. Make sure to:
- Wash and peel potatoes to remove most solanine
- Dice potatoes and boil until very soft in ample water
- Drain boiled potatoes well before mashing
Straining excess water during cooking can help further reduce any glycoalkaloids. The mashing process may also help distribute solanine evenly for lower concentrations per bite.
However, potatoes with pronounced greening, sprouting or bitterness should not be used to make mashed potatoes, as solanine levels may be too high even after peeling and boiling.
Can you eat fried green potatoes like french fries or chips?
It’s riskier eating deep fried green potatoes compared to boiling/cooking them in water. Frying does not reduce solanine levels, and may even concentrate toxins with water evaporation.
Potato varieties high in reducing sugars like russets are also more prone to acrylamide formation during frying and baking, which may pose other health risks.
That said, french fries or chips made from peeled, mildly green potatoes are likely safe in moderation. Make sure to peel them thickly and discard severely discolored potatoes.
What potato varieties tend to green more easily?
Some potato varieties are more prone to greening and solanine production when exposed to light. Varieties that tend to green more include:
- Russet potatoes
- Long white potatoes
- Round white potatoes
- Purple potatoes
Other all-purpose and waxy potatoes like Yukon Gold or red potatoes are less inclined to develop green color. Fingerling or baby potato varieties also green less often due to their thin skin.
Do green potatoes mean the entire crop is bad?
Finding some green potatoes in a crop does not necessarily mean the entire batch is unsafe or should be discarded. Greening is often sporadic based on micro-conditions the individual tuber was exposed to.
Sort through the harvest and set aside any pronounced green or sprouted potatoes to feed to livestock. Potatoes with just slight green tinges can still be eaten after peeling and proper cooking.
Test for bitterness by nibbling a tiny raw slice from green-tinged potatoes. A bitter taste indicates higher glycoalkaloid levels.
Are potato sprouts safe to eat?
No, potato sprouts should always be removed before cooking and eating the spuds. The sprouts and eyes of potatoes contain very high concentrations of glycoalkaloids like solanine.
Even just a small nibble of a potato sprout can make someone ill. Make sure to cut off any sprouts and discolored tissue around them.
Can you eat green potato skins?
Potato skins, especially green potato skins, should not be eaten. Most of the glycoalkaloids in a potato are found concentrated in the peel and immediate subsurface layers.
Eating green potato skins risks a much higher solanine dose and greater risk of toxicity. Always peel green tinged potatoes thickly before cooking and discard the skins.
What causes potatoes to turn green?
Greening in potatoes is caused by exposure to light. When potatoes are grown in the dark underground, they remain white. But light exposure causes the tuber to start producing chlorophyll, giving it a green tint.
This light-induced chlorophyll triggers increased glycoalkaloid production to deter insects and predators. More sun exposure equals more greening.
How can I prevent potatoes from turning green while growing?
To minimize greening, growers need to limit light exposure while the potato plant is maturing. This can be done by:
- Hilling soil over the plants as they grow to block light
- Growing potatoes under a dense plant canopy like corn that provides shade
- Using straw mulch to protect tubers from light
Rotate potato crop locations yearly to avoid phytophthora fungus that can cause potatoes to appear green prematurely as vines die back.
Can potatoes become green after harvest?
Yes, potatoes can turn green even after being harvested if they are exposed to too much light during storage or transport. Proper post-harvest handling is important to prevent greening.
- Store potatoes in a cool, dark place like a basement or closet.
- Keep potato bags or boxes away from light sources.
- Avoid storing potatoes at warm temperatures, which accelerates solanine production.
Grocery stores should also take care to prevent display potatoes under bright lights from greening through rotation and limiting light exposure.
Do green potatoes taste different?
Green potatoes may have a slightly bitter or earthy flavor compared to normal potatoes. This bitterness comes from the increased glycoalkaloids.
A bitter taste is a warning sign that solanine levels are higher. Use caution when tasting green potatoes and avoid eating ones with a pronounced bitter taste.
With mild greening, any bitterness is usually only noticeable when potatoes are eaten raw. Properly cooked green potatoes often taste relatively normal.
Can you make vodka or liquor from green potatoes?
It’s not recommended to make vodka or moonshine from green potatoes. The glycoalkaloid toxins can carry over into the distilled spirits and make people sick.
Some moonshiners may unknowingly use green or sprouted potatoes if they use a whole potato mash. The safest approach is to only use sound, white potatoes for fermenting and distilling.
Are green potato chips safe?
Sometimes green-tinged potato chips can be found in bags of store bought chips. These are usually safe to eat in moderation if sourced from commercial potato growers.
The high heat of frying does not degrade glycoalkaloids like solanine. However, green chips from commercially grown potatoes likely have low enough solanine levels to not cause issues when eating a small serving.
That said, unusually green chips with a bitter taste should be avoided, as they may have excessively high toxin levels.
Can dogs eat green potatoes?
It’s best to avoid feeding dogs green potatoes. Canines are more sensitive to glycoalkaloids than humans. Feeding dogs even small amounts of green potatoes could cause gastrointestinal issues.
Some other human foods toxic to dogs include:
- Grapes and raisins
- Chocolate
- Caffeine
- Alcohol
- Onions
- Garlic
Stick to plain, cooked white potatoes if you want to share some spuds with your dog.
Can chickens eat green potatoes?
Small amounts of green potatoes are not typically harmful to chickens. In fact, many homesteaders safely feed their chicken flocks cull potatoes, sprouts and peelings.
However, moderation is still recommended. Too much solanine from heavily green potatoes could impact chicken health and egg-laying capabilities.
Make green potatoes just a small part of a balanced chicken diet with grains, bugs, fruits and vegetables. Also cook potatoes before feeding for easier digestion.
Conclusion
While green potatoes have elevated glycoalkaloid levels compared to normal white potatoes, the small amounts found in most commercially grown green potatoes are unlikely to cause poisoning when consumed after peeling and proper cooking. Still, pronounced greening, bitterness and sprouting are telltale signs to avoid eating those tubers. With common sense preparation and moderation, green potatoes can be safely enjoyed by humans, but should be avoided when feeding pets and livestock.
