Sweetness is a major component of flavor. Measurements of soluble solids in muskmelon juice using a refractometer measure its sugar content and hence sweetness. United States Standards for Grades of Cantaloups require that U.S. Fancy melons have at least 11% soluble solids and that U.S. No. 1 have at least 9% soluble solids. Lesser grades have no stated requirement. Muskmelons have a distinctive aroma that contributes to flavor. Muskmelon varieties will vary in sugar content and these differences are reported annually in the Midwestern Vegetable Variety Trial Report

Healthy vigorous vines and leaves are essential for sugar development. Drought and nutrient deficiencies can limit sugar development. Boron and magnesium are associated with sugar formation in the cell, deficiencies in either of these elements may contribute to low soluble solids. Cloudy, cool temperatures and excessive rainfall, especially near or during the time of harvest can also limit sugar development. Avoid excessively high plant populations. A general rule of thumb is that 6 square feet of effective leaf area per plant is required for muskmelon to achieve an acceptable sugar content. Most planting recommendations specify that 15 or more square feet of space should be allowed per plant. Crown set fruit are often higher in sugar than later fruit. Recommendations for fertilizing and spacing are available in the Midwest Vegetable Production Guide or through your local Cooperative Extension Service.

Fungal diseases such as anthracnose, alternaria and gummy stem blight on the foliage can reduce soluble solids.Anthracnose will also infect the fruit resulting in lesions on the outside of the fruit.

Muskmelons are harvested by maturity and not by size. As the melon approaches maturity it develops an abscission layer at the joint where the fruit is attached to the stem.  When this layer has completely formed the fruit is at the "full slip" stage and contains the highest amount of sugar it will attain under the conditions the plant was grown. If muskmelons are to be shipped some distance to market it is advisable to harvest just before reaching "full slip" to avoid excessive losses from over-ripeness and decay. Frequent harvests, especially in hot weather, are necessary to avoid over-maturity of the muskmelon. Harvest workers must be careful to cause as little damage to the vine as possible to minimize loss in photosynthetic activity.

Some muskmelon varieties may be stored up to 15 days at 36˚F to 41˚F but flavor will be reduced as the end of the storage term is reached.

Muskmelons are graded for quality by the amount of exterior netting present. This exterior texture is variable among varieties. A fruit must be "well netted" to receive a U.S. Fancy or U.S. No.1 grade. Netting is a quantitatively inherited trait, which means the trait is controlled by several to many genes. In this situation it means that the expression of netting can be influenced by numerous environmental factors. On 'western' muskmelons netting is denser than on 'eastern' muskmelons and eastern muskmelons have ribs that distinguish them in the market. Netting characteristics of numerous varieties are reported in the annually published Midwestern Vegetable Variety Trial Report.

Interior flesh texture is also a component of quality. It can be firm, somewhat stringy or even soft to mushy. Firmness is a varietal characteristic but it may also be an indication of immaturity. Some varieties of muskmelons have interior flesh that is too soft at optimum maturity. Flesh thickness is the most stable of fruit quality characteristics. Flesh thickness is related to both fruit size and seed cavity size. A large melon with a small seed cavity is ideal.

Stress conditions from any source can have a negative impact on net development. About two weeks after pollination the surface of the enlarging fruit starts to develop fine cracks and continues to do so for 7 to 10 days. Corky cells associated with the fine cracks begin to develop into netting and this process continues until full slip. Stress during this period hinders the development of the netting. Examples of stress conditions include lack of nutrition, drought or excessive moisture, restriction of the root system, damage to the foliage and temperature extremes.

Stress conditions due to disease, insect or weed pressure during net development can reduce the quality of the netting. Recommendations for pest management are available in the Midwest Vegetable Production Guide or through your local Cooperative Extension Service.

The quality of the flesh texture is related to harvesting muskmelon at 1/2 to full slip. Earlier harvest will likely result in flesh that is too firm. Harvest past full slip may result in soft or even mushy flesh. Late harvest may also result in water accumulating in the seed cavity.

The texture of the flesh deteriorates toward the end of extended storage. Rapid pre-cooling to 40˚F after harvest will result in better post harvest keeping quality. Storage and transit temperatures between 36˚ to 41˚F are optimal.

The color of developing fruit is light green. The background color changes to light yellow by 1/4 slip. The internal flesh color varies by cultivar, but reaches its greatest intensity at maturity. Color intensity can be reduced by stress conditions during fruit development.

Potential size of muskmelon fruit is determined by genetics. The average size of numerous muskmelon varieties is reported in the annually published Midwestern Vegetable Variety Trial Report. Pollination also has a direct effect on size. Muskmelon flowers are self-fertile, but require insects to transfer pollen. There must be sufficient bee activity during the one day the female flower is open to insure that more than 400 seeds are formed. Fruit with less than 400 seeds are usually so small they are classified as culls. The more seeds the larger the fruit.

The average fruit size will vary for a given variety from season to season by as much as 15% depending on growing conditions and pollination. Soil conditions, temperature and moisture are major variables. If plant population exceeds the recommended population, smaller average size should be expected. Recommended plant spacing is available in the Midwest Vegetable Production Guide or from your local Cooperative Extension Service.

Insect, disease and weed pressure will result in reduced average fruit size.

Muskmelon fruit shape is controlled by genetics. Traditionally eastern muskmelons have pronounced ribs and western muskmelons are not ribbed. The distinction is less evident with some of the newer eastern varieties. Large melons may develop a flat side where they lay on the ground. Melons from virus infected vines may have irregular shape.

United States Standards for Grades of Cantaloups identifies some defects that are of concern to the trade. They include overripeness or softness, poor netting, decay, wet slip, sunscald, damage caused by liquid in the seed cavity, sunburn, hail, dirt, surface mold or other disease, aphids or other insects, scars, cracks, sunken areas, ground spot, and bruises.

The shelf life of muskmelon varies considerably by variety. Athena may store better than most varieties. Harvest timing is also important. Muskmelons harvested at 1/2 or 3/4 slip will store longer than those harvested at full slip. Cooling is perhaps the most important determinant of shelf life. Rapid pre-cooling to 40˚F after harvest will result in better post harvest keeping quality. Storage and transit temperatures between 36˚ to 41˚F are optimal. The storage period before the fruit becomes unmarketable may range from 5 to 18 days at 40˚F. Western type melons may store more consistently toward the higher range, but sensory quality may be reduced after two weeks in storage.