The investigation of water extracted from sediments by various means plays an important role in soil science, the environmental sciences, and hydrogeology, but so far it has been problematic to directly extract from material with low moisture contents. Arklone (F113) had been proved to be a good displacing fluid in the past. However, because of its environmental drawbacks, the usage of Arklone was banned in the late 1980s. We present a new immiscible liquid, HFE-7100, which has similar physical and chemical properties to Arklone; we show that HFE-7100 can be used to replace Arklone for environmental research in the unsaturated zone. We compared interstitial water extracted from two unsaturated sandstone profiles from southern England using both HFE-7100 and Arklone. Results showed that the high-speed centrifuge technique with the use of HFE-7100 offers a reliable, rapid, safe, affordable, and nondestructive method for extracting unaltered interstitial water from unsaturated sediments. The HFE-7100 has comparable properties to Arklone, with yields between 20 and 80%.