mada, i dry my own grapes from my vines at the end of september, but if you don't want to wait you can always buy some now and do the same thing....if you can find organic ones its better!
Remove very ripe grapes from their stems, keep the most perfect ones and wash then dry them. The skins have to be cracked to enable them to dry faster, dip them into into boiling water for 30 seconds to one minute. Drain the grapes after boiling.
Then give them an antimicrobial bath which will prevent the formation of mold as the grapes are dried and stored. Mix a solution of one part lemon juice and one part water. Place the grapes in the antimicrobial solution for 10 minutes then remove, drain and pat dry.
Allow them to dry in the sun spead evenly on a tray, under an aired cover, i use a 'dome' with tiny holes in it to allow the air to pass, and turn them from time to time.