There is ongoing interest for evaluating the potential of renewable base stocks, such as vegetable oils, to replace petroleum oils as metal quenchants. Perhaps the most critical part of this process is characterizing and comparing the cooling and heat transfer performance of potential quenchant candidates. In this work, cooling curves of two vegetable oils, palm oil and canola oil, were obtained along with a commercially available conventional and an accelerated petroleum quenchant using the so-called Tensi multiple thermocouple probe, with emphasis on the center probe emulating a small probe concept. The lumped-parameter approach was implemented in the MATLAB environment (Mathworks Inc., Natick, MA). Experimental quenching data along with temperature-dependent thermal properties for the Inconel probe material were used to quantify the cooling characteristics and heat transfer properties of two typical vegetable and petroleum oil quenchants. The results obtained exhibited a fundamental difference in the cooling characteristics between the vegetable oils and also between both vegetable oils and the petroleum oil quenchants evaluated. The focus of this article will be on the development of the computational codes and the use of MATLAB to perform these analyses.