Set sous vide machine to 85C/185F.
Add corn, butter and salt in sous vide bag and remove air through a vacuum sealer or the displacement method. Drop the bag in the bath for 30 minutes.
Remove bag from bath and place corn on cutting board. Using a chef's knife, cut from the top to bottom shaving off the kernels from the cob.
In a large bowl, add corn kernels, mayonnaise, cotija cheese, lime juice, salt and chili powder. Toss to evenly combine, and enjoy!