I am an agriculturist and going to conduct my research on grape in order to determine the ripeness level in a grape bunch. For your information, a grape bunch contains around 50-80 individual grapes. My question, how to determine minimal number of sample to be taken and sampling technique (cluster/stratified/random?)on individual fruit in a bunch (in here we consider that in a bunch each individual grape has different ripeness due to the sunlight, their sensitivity and so on). Many thanks for your incorporation.