Pentanol is slightly higher in surface tension, but there isn't much in it. From memory I believe methanol is around 22 mN/m at 20 celcius, whilst n-pentanol is about 3 nN.m higher.
Surface tension is basically the amount of energy that is involved in the creation of an interface. In other words, if the surface tension is zero, then there is no interface formed (100% miscibility). The somewhat longer alkyl chain of n-pentanol compared with methanol means that there is a increased number of -CH2- units whose contact with water is not energetically favourable. Hence the slightly higher surface tension.