1. If you blanch it in water, 2 minutes is enough.

2. Ingredients: appropriate amounts of white vinegar, rock sugar, wolfberry, and yam;

3. First prepare the white vinegar and rock sugar, wash the wolfberry, and soak it in clean water. Prepare the yam. Add it to the clean water. Just the right amount of white vinegar.

4. Next, peel and cut the yam into strips and soak it in vinegar water. After the water in the pot is boiled, add the yam and boil over high heat for 4 minutes. Remove it. Pour the water for soaking the wolfberry into the pot and add it. Bring the rock sugar to a boil over high heat.

5. Then add an appropriate amount of white vinegar to make it sweet and sour and turn off the heat.

6. Finally, soak the yam strips in sweet and sour water for an hour before eating them to make them more delicious. You can refrigerate them before eating them. They are sour, sweet and crispy.