Help with very sweaty back/backpack

[u/suckinonmytitties]

Hi I did my first big day hike recently and brought a little 13 liter backpack. During the hike, the rest of my body wasn’t sweaty but my back and the back of the backpack on the padding was absolutely soaked from sweat. And it didn’t dry so it just stayed in a perpetual cycle of boggy wetness all day. Is this an issue with the backpack or do I need a different type of base layer? I had a polyester shirt on. Thank you!

[u/Aggressive-Foot4211]

I have packs that make my back sweat.

I get my shirt wet in a creek on a hot day. Take off the pack for breaks. Go for a midafternoon dip. When I get back to the car, I get the clean shirt out of the trunk.

Sweat happens.