42+ How To Keep Fresh Raspberries Viral. Swish the berries around with your fingertips to loosen any dirt. With clean hands, gently place the raspberries in the vinegar bath. Freezing Raspberries {How to Freeze Raspberries} Sustainable Cooks from www.sustainablecooks.com Toss the berries with the starch and sugar before adding it to the baking dish and …