It's Here And It's Big! The New 64 oz Hydro Flask Growler! The Hydro Flask Growler is the ideal size for filling up with your beer of choice from the local brewery and then taking that IPA or Porter to trails. Or head up to the mountain with the growler and have some coffee, hot cocoa, or hot soup waiting for you and the crew at the end of the day. The Hydro Flask Growler is perfect for keeping your chili hot from the kitchen to the cook-off. The wide mouth growler features Hydro Flask's largest opening and is .375 inches wider than our standard mouth bottles.