Abstract1) Air adsorbed on potato tuber surface can result the accidental error, decreasing the true value of tuber density. Some deviations from normal temperature do not seem to change substantialy the tuber density.2) The dry matter determination should be precisely reexamined in a special series of experiments. The improper method can introduce a systematic error, increasing or decreasing the results.3) It is necessary to compare mostly used methods of starch determination in potato tubers and to estimate the possible systematic errors.4) The various slope of the regression line: dry mater/starchvs.potato density, can be resulted by different factors as follows: the variable intercellular spaces, the proportional systematic errors in analytical determination, the variable dry matter density, and increasing (or decreasing) value of non‐starch substances.5) The intercellular spaces can result either a constant or a proportional systematic errors in the tuber density determination. They can be eliminated by vacuum infiltration procedure, which should be, however, verified.6) The dry matter determination seems to be difficult analytical problem and it has not been definitely solved until now.7) TheMaercker's constant has been until now an open question and its variability should be verified from analytical point of vie