How raisins are classified according to: color, grade, size and quality

Introduction

It is no secret that raisins are made from dried grapes, but not everyone knows how many different types of grapes there are that are specially grown for being turned into raisins. Raisin varieties depend on the type of grape that is used and are divided according to size, color (green, black, brown, blue, purple and yellow), quality and variety (raisins, sultanas and currants).

Some are grown seedless, some are unseeded after harvest and some just have seeds. In any case, every name, type, grade and method will be clarified in this article. Keep reading, grape lovers!

Disclaimer: It is important to clarify that, in this article, every existing classification has been included, but there is still not a global agreement regarding the nomenclature, for example, in the United States, the term raisin applies for both raisins and sultanas, whilst sultanas are referred to as "golden raisins". Internationally, in most countries, raisins and sultanas are differentiated by the type of grape and the processing method used.

In general, raisins are made out of low-sourness, sweet, small-sized and seedless grapes, the main ones being Sultanas (Thompson Seedless variety), Muscat and Zante Currants.

One type of seeded raisin is the Monukka raisin. This is a large, dark, sweet raisin with noticeable seeds. Some people prefer it for its traditional appearance and flavor; others, like the fact that grape seeds are touted as having magical health properties. It is a tasty type of raisin but not everyone appreciates the seeds.

Classification according to the type of grape

Raisins

Raisins are those defined for being made out of white-fleshed grapes, and dried from around three weeks. However, they darken as the dry, which is what gives them their typical dark brown color. They are naturally dark in color, soft textured, sweet-flavored and larger than sultanas and currants.

In the United States, raisins are made from the Thompson Seedless variety. Whilst in Australia, for example, raisins are made exclusively from larger grape varieties including Muscat, Lexia and Waltham Cross, often larger than sultanas for this reason.

Some methods consist on dividing grapes depending on the grape color:

• Black raisins: this qualifies as the most common type of raisin, and can be made out of any grape type and color. The higher the heat and more direct the sunlight (during the drying process), the darker it gets.

• Red raisins: produced from red-skinned grapes. They are also known as flame, which comes from the Flame Seedless red grape and it is large, plump, dark red and sweet-tart.

• Green raisins: these are slim, from 2 to 3 cm (0.79 to 1.18 in) long, dense, chewy and lightly tart. Usually dehydrated in well aired dark indoor conditions.

Sultanas

These are mostly made from green seedless grapes, particularly the Thompson Seedless variety. Their drying process is sped up by coating the sultanas in an oil-based solution, which makes them lighter in color than raisins and currants. They are smaller than raisins and sweeter, juicer and lighter in color than raisins and currants. Since they are the sweetest, these are commonly used in deserts and pastries.

For example, in Australia, some sultanas are made without the drying solution, an they take up to three weeks to dry and are dark brown-colored, referred to as "natural sultanas". In the United states, sultanas are referred to as "golden raisins" or sultana raisins. They treat them with a preservative called sulfur dioxide that helps retain the light color of the grapes.

Currants

Actually, currants are not essentially grapes. They are an ancient variety of grape that is still used to make dried fruit. However, nowadays, currants or Zante currants, denote a type of very small, seedless grapes, generally Black Corinth and Carina. They are dried up for up to three weeks and result in small, sweet, tangy and intense-flavored dried grapes.

Original black currants are hard quite tart and grow on bushed instead of vines. These are very hard to find and this type of dried fruit also applies to the gooseberry family.

Grades and standards for processed raisins

Other method of classification is by the USDA Raisin Grades and Standards. This consists on classifying grapes according to different selected features into six types, each with different quality grades. Raisins are included in types I, II and II, Sultanas are type IV, Currants are type V and type VI is for classifying mixed types of raisins.

Type I includes only seedless raisins.

- Size

• Select size: up to 60% (by weight) of raisins should pass through holes of 22/64-inch in diameter. However, not more than 10% of the total raisins must fit in 20/64-inch holes.
• Small size: 95% of the total must pass though round perforations of 24/64-inch in diameter, but not less than 70%, should pass through holes of 22/64-inch.
• Mixed size: those that do not meet the conditions for either small nor select sizes.

- Grades

• Grade A seedless raisins: up to 80% of the total raisins' weight show: good typical colors, good characteristic flavor, a nice development for well-matured grapes, not more than 18% of moisture.
• Grade B: the quality grade of seedless raisins that show good typical colors, good characteristic flavor and up to 70% (by weight) of the total show well-maturity or reasonably well-maturity, and contain not more than 18% moisture.
• Grade C: these show fairly good typical color, have fairly good flavor, and not more than 55% (by weight) are well-matured or reasonably well-matured. In addition, they may contain up to 18% (by weight) of moisture.
• Substandard: these raisins fail to meet requirements of quality Grade C.

Type II Golden seedless raisins.

- Colors

• Well colored: color uniformity, range from yellow or golden to light amber, predominately yellow or golden, and not over 0.5% of all raisins may be definitely dark berries.
• Reasonably well colored: reasonably uniform in color, ranging from yellow or golden or greenish yellow to light amber, predominately greenish yellow or light amber, and not over 3% of all raisins may be definitely dark berries.
• Fairly well colored: raisins are fairly uniform in color and may range from yellow or greenish yellow to amber or light greenish amber, and up to 6% (by weight) of the total of raisins may be definitely dark berries.
• Colored: raisins may be variable in color and may range from yellowish green to dark amber or dark greenish amber, and not more than 20% of all raisins may be definitely dark berries.
• Definitely dark berries: those raisins that are definitely darker than dark amber.

- Size

Size classification is the same as for Seedless raisins: select size, small size and mixed size.

- Grades

The grades for golden seedless raisins are the same as for seedless raisins.

Type III raisins with seeds.

This type of raisins does not qualify for the finished products' grades

(a) except layer or cluster

Seeded

- Size

• Select size: up to 70% (by weight) of the raisins will pass through 34/64-inch holes, and not over 5% of the total of raisins will pass through 22/64-inch holes.
• Small size: the total of raisins should pass through round perforations of 34/64-inch and not less than 90Ç% will pass through 22/64-inch holes in diameter.
• Mixed size: these do not meet the conditions to be neither select nor small sized raisins.

- Grades

• Grade A: raisins show good typical color, have a good characteristic flavor, and under a 10% may be dark reddish-brown berries. Not less than 80% of the total weight are well-matured or reasonably well-matured. Finally, they contain not more than 18% of moisture.
• Grade B: good typical color, good flavor, not over 15% of the total raisins may be dark reddish.-brown berries. Not less than 70% of the total are well-matured or reasonably well-matured, and not more than 18% of moisture.
• Grade C: fairly good typical color, fairly good flavor, prepared from well-matured grapes, and not more than 20% (by weight) may be dark reddish-brown berries- Finally, they contain not more than 18% of moisture.
• Substandard: these raisins fail to meet requirements of quality Grade C.

Unseeded

• 4 Crown: these raisins will not pass through 42/64-inch holes.
• 3 Crown: these will pass through round perforations of 42/64-inch in diameter but not through 34/64-inch holes.
• 2 Crown: raisins that will pass through round perforations of 34/64-inch but not through 24/64-inch holes.
• 1 Crown: these raisins will pass through round perforations of 24/64-inch in diameter.

(b) layer or cluster

Seeded

- Size

• 3 Crown Size or Larger: this means that the raisins with stems and branches are such size that will not be able to pass through 34/64-inch holes.

- Grades

• Grade A: good typical color, good characteristic flavor, uniformly cured and are prepared from well-matured grapes, contain not more than 20% of moisture, and not less than 30% of the raisins are 3-Crown size or larger.
• Grade B: reasonably good typical color, good characteristic flavor, uniformly cured and are reasonably well-matured. These do not contain more than 23% of moisture, and not less than 30% of the raisins are 3-Crown size or larger.
• Substandard: these raisins fail to meet requirements of quality Grade B.

Type IV Sultanas

- Size

Size designations are not applicable to sultana raisins

- Grade

• Grade A: these raisins present good typical color, good characteristic flavor, not less than 80% of the raisins are well-matured and contain not more than 18% of moisture.
• Grade B: these show reasonably good color, good characteristic flavor, not less than 70% of raisins are well-matured or reasonably well-matured and contain not more than 18% of moisture.
• Grade C: these raisins should show  fairly good color, fairly good flavor and contain not more than 18% of moisture.
• Substandard: these raisins fail to meet requirements of quality Grade C.

Type V Zante Currants

- Size

Size designations do not apply for this type of raisins.

- Grades

• Grade A: are, on a 75% by weight, those that have similar varietal characteristics: good typical color, good characteristic flavor, show development characteristics of raisins made from well-matured grapes. Last, they contain not more than 20% by weight of moisture.
• Grade B: these raisins have a reasonably good typical color, good characteristic flavor, have development characteristics of raisins prepared form reasonably well-matured or fairly well-matured grapes, and  contain not more than 20% of moisture.
• Substandard: is the quality grade that fails to meet the requirements from the Grade B properly processed raisins.

Type VI Mixed types of raisins

Grades of mixed types of processed raisins should be positioned as the lowest of any type, except for the moisture level. Mixed types of processed raisins of Grade A, B or C may contain not more than 18% of moisture, whilst those that exceed 18% of moisture classify as Substandard.

References

https://www.inta.gob.ar

https://www.ams.usda.gov

https://www.fao.org