I read in a book recently that you can not get big eyes in small swiss cheeses because the percentage of "holes" form is so small that most are lost before they have time to develop.
From Cheese Problems Solved
The saturation concentration of carbon dioxide in Emmental is around
34mmol kgÿ1 and depends on pH and temperature of the cheese body. At 10 ëC, 50% more carbon dioxide is soluble than at 20 ëC; at a pH of 4.8 twice as much CO2 is soluble than at pH 5.2. The high pH of Swiss-type cheeses and the ripening step in the warm room are therefore two important factors that are responsible for a lower solubility of CO2 and consequently for better eye development.
A soft and elastic texture is crucial for a regular eye formation. This is why
the technology of Emmental cheese production is aimed at the achievement of optimum conditions not only for propionic acid fermentation, but also for the development of a soft and elastic texture. Furthermore, the rind is also essential for eye formation. Brining of the cheeses for 2±3 days and the rather low relative humidity in the ripening room (70±80%) lead to a firm and dry rind , which reduces the loss of CO2. The brining and the low relative humidity of the ripening room results in a loss of water from the rind and, consequently, to a compact protein network at the surface of the cheese, which acts as a barrier for gas diffusion. If the rind is too soft and too porous, the brine can be supplemented with calcium, which leads to a stronger protein matrix. On the other hand, if the rind is too rigid, the calcium available in the brine can be eliminated by precipitation. Thus the porosity of the rind can be controlled by adding or removing calcium.