1. Aluminum alloy pressure cooker
Ordinary pressure cookers are aluminum pots (including aluminum alloy), but stainless steel pressure cookers are also sold in the market, but the price is higher. The pressure cooker people usually say refers to the ordinary aluminum pressure cooker. The aluminum pressure cooker can hold rice and other non-acid, non-alkali, and non-salty foods for a long time (but not recommended). But its acid resistance, alkali resistance, and salt resistance are not very good, because the surface coating is alumina, which will react chemically with the acid, alkali, and salt substances in the food, and most foods are acidic and salty. Therefore, it is best not to use an aluminum pressure cooker to hold food for a long time.
2. Stainless steel pressure cooker
Stainless steel pressure cooker is heavier and brighter than aluminum, and it is also more resistant to acids, alkalis and salts. However, stainless steel is good or bad. Type 340 has poor acid and alkali resistance. Type 304 stainless steel is in the middle, and type 316 and 316L have very good resistance to acid-base salt. So, if you know that you are buying a stainless steel pressure cooker made of 316L, it can hold any food for a long time, but if you are not sure about the stainless steel model, it is better not to hold food for a long time!