Lifelines are cut off during disasters. As a result, water, gas, and electricity cannot be used, making it impossible to prepare meals. If you always have ready-to-eat porridge, you do not need to cook it, and can eat it whenever you want. The porridge with a lot of water causes aspiration in older people. In welfare facilities and hospitals, a thickener is used to adjust the viscosity of porridge so that the elderly can safely swallow it. In this study, we measured the thickness of commercially available porridge using the line spread test (LST). First, the viscosity of commercially available white rice porridge was assumed. Next, the white rice porridge was homogenized with a mixer, and the thickness was measured. Two g of each of the four commercially available thickeners was added to white rice porridge, homogenized with a mixer, and the viscosity was measured after stirring for five minutes. Viscosity measurements were taken 30 seconds, 5 minutes, 15 minutes, and 30 minutes after each porridge placed on the measuring plate. When the white rice porridge was homogenized using a mixer, the viscosity became thin, and there was the risk of aspiration.