in determining honey flavors and aromas. vocs are carbon-based compounds that readily vaporize into the air, providing aroma, including the scents of flowers, essential oils, or ripening fruit. the typical chemical families of vocs found in honey include hydrocarbons, aldehydes, alcohols, ketones, esters, acids, benzenes, furans, pyrans, norisoprenoids, and terpenes, among many others and their derivatives. the specific vocs and their amounts vary considerably between different types of honey obtained by bees foraging on different plant sources. by example, when comparing the mixture of vocs in different honeys in one review, longan honey had a higher amount of volatiles (48 vocs), while sunflower honey had the lowest number of volatiles (8 vocs). vocs are primarily introduced into the honey from the nectar, where they are excreted by the flowers imparting individual scents. the specific types and concentrations of certain vocs can be used to determine the type of flora used to produce monofloral honeys. the specific geography, soil composition and acidity used to grow the flora also have an effect on honey aroma properties, such as a "fruity" or "grassy" aroma from longan honey, or a "waxy" aroma from sunflower honey. dominant vocs in one study were linalool oxide, trans-linalool oxide, 2-phenylacetaldehyde, benzyl ethanol, isophorone, and methyl nonanoate. vocs can also be introduced from the bodies of the bees, be produced by the enzymatic actions of digestion, or from chemical reactions that occur between different substances within the honey during storage, and therefore may change, increase, or decrease over long periods of time. vocs may be produced, altered, or greatly affected by temperature and processing. some vocs are heat labile, and are destroyed at elevated temperatures, while others can be created during non-enzymatic reactions, such as the maillard reaction. vocs are responsible for nearly all of the aroma produced by a honey, which may be described as "sweet", "flowery", "citrus", "almond" or "rancid", among other terms. in addition, vocs play a large role in determining the specific flavor of the honey, both through the aromas and flavor. vocs from honeys in different geographic regions can be used as floral markers of those regions, and as markers of the bees that foraged the nectars. classification honey is classified by its floral source, and divisions are made according to the packaging and processing used. regional honeys are also identified. in the us, honey is also graded on its color and optical density by usda standards, graded on the pfund scale, which ranges from 0 for "water white" honey to more than 114 for "dark amber" honey. floral source generally, honey is classified by the floral source of the nectar from which it was made. honeys can be from specific types of flower nectars or can be blended after collection. the pollen in honey is traceable to floral source and therefore region of origin. the rheological and melissopalynological properties of honey can be used to identify the major plant nectar source used in its production. blended most commercially available honey is a blend of two or more honeys differing in floral source, color, flavor, density, or geographic origin. polyfloral polyfloral honey, also known as wildflower honey, is derived from the nectar of many types of flowers. the taste may vary from year to year, and the aroma and the flavor can be more or less intense, depending on which flowers are blooming. monofloral monofloral honey is made primarily from the nectar of one type of flower. monofloral honeys have distinctive flavors and colors because of differences between their principal nectar sources. to produce monofloral honey, beekeepers keep beehives in an area where the bees have access, as far as possible, to only one type of flower. in practice a small proportion of any monofloral honey will be from other flower types. typical examples of north american monofloral honeys are clover, orange blossom, sage, tupelo, buckwheat, fireweed, mesquite, sourwood, cherry, and blueberry. some typical european examples include thyme, thistle, heather, acacia, dandelion, sunflower, lavender, honeysuckle, and varieties from lime and chestnut trees. in north africa (e.g. egypt), examples include clover, cotton, and citrus (mainly orange blossoms). the unique flora of australia yields a number of distinctive honeys, with some of the most popular being yellow box, blue gum, ironbark, bush mallee, tasmanian leatherwood, and macadamia. honeydew honey instead of taking nectar, bees can take honeydew, the sweet secretions of aphids or other plant-sap-sucking insects. honeydew honey is very dark brown, with a rich fragrance of stewed fruit or fig jam, and is not as sweet as nectar honeys. germany's black forest is a well-known source of honeydew-based honeys, as are some regions in bulgaria, tara in serbia, and northern california in the united states. in greece, pine honey, a type of honeydew honey, constitutes 60–65% of honey production. honeydew honey is popular in some areas, but in other areas, beekeepers have difficulty selling honeydew honey, due to its stronger flavor. the production of honeydew honey has some complications and dangers. this honey has a much larger proportion of indigestibles than light floral honeys, thus causing dysentery to the bees, resulting in the death of colonies in areas with cold winters. good beekeeping management requires the removal of honeydew prior to winter in colder areas. bees collecting this resource also have to be fed protein supplements, as honeydew lacks the protein-rich pollen accompaniment gathered from flowers. honeydew honey is sometimes called "myelate". classification by packaging and processing a variety of honey flavors and container sizes and styles from the 2008 texas state fair generally, honey is bottled in its familiar liquid form, but it is sold in other forms, and can be subjected to a variety of processing methods. crystallized honey occurs when some of the glucose content has spontaneously crystallized from solution as the monohydrate. it is also called "granulated honey" or "candied honey". honey that has crystallized (or is commercially purchased crystallized) can be returned to a liquid state by warming. pasteurized honey has been heated in a pasteurization process which requires temperatures of 72 °c (161 °f) or higher. pasteurization destroys yeast cells. it also liquefies any microcrystals in the honey, which delays the onset of visible crystallization. however, excessive heat exposure also results in product deterioration, as it increases the level of hydroxymethylfurfural (hmf) and reduces enzyme (e.g. diastase) activity. heat also darkens the honey, and affects taste and fragrance. raw honey is as it exists in the beehive or as obtained by extraction, settling, or straining, without adding heat (although some honey that has been "minimally processed" is often labeled as raw honey). raw honey contains some pollen and may contain small particles of wax. strained honey has been passed through a mesh material to remove particulate material (pieces of wax, propolis, other defects) without removing pollen, minerals, or enzymes. filtered honey of any type has been filtered to the extent that all or most of the fine particles, pollen grains, air bubbles, or other materials normally found in suspension, have been removed. the process typically heats honey to 66–77 °c (150–170 °f) to more easily pass through the filter. filtered honey is very clear and will not crystallize as quickly, making it preferred by supermarkets. the most common method involves the addition of diatomaceous earth to honey that is heated to 60 °c (140 °f) and passed through filter paper or canvas until a filter cake of diatomaceous earth builds up on the filter. ultrasonicated honey has been processed by ultrasonication, a nonthermal processing alternative for honey. when honey is exposed to ultrasonication, most of the yeast cells are destroyed. those cells that survive sonication generally lose their ability to grow, which reduces the rate of honey fermentation substantially. ultrasonication also eliminates existing crystals and inhibits further crystallization in honey. ultrasonically aided liquefaction can work at substantially lower temperatures around 35 °c (95 °f) and can reduce liquefaction time to less than 30 seconds. creamed honey, also called whipped honey, spun honey, churned honey, honey fondant, and, in the uk, set honey, has been processed to control crystallization. creamed honey contains a large number of small crystals, which prevent the formation of larger crystals that can occur in unprocessed honey. the processing also produces a honey with a smooth, spreadable consistency. dried honey has the moisture extracted from liquid honey to create completely solid, nonsticky granules. this process may or may not include the use of drying and anticaking agents. dried honey is used in baked goods, and to garnish desserts. comb honey is still in the honeybees' wax comb. it is traditionally collected using standard wooden frames in honey supers. the frames are collected and the comb is cut out in chunks before packaging. as an alternative to this labor-intensive method, plastic rings or cartridges can be used that do not require manual cutting of the comb, and speed packaging. comb honey harvested in the traditional manner is also referred to as "cut-comb honey".: 13 chunk honey is packed in wide-mouthed containers; it consists of one or more pieces of comb honey immersed in extracted liquid honey.: 13 honey decoctions are made from honey or honey byproducts which have been dissolved in water, then reduced (usually by means of boiling). other ingredients may then be added. (for example, abbamele has added citrus.) the resulting product may be similar to molasses. baker's honey is outside the normal specification for honey, due to a "foreign" taste or odor, or because it has begun to ferment or has been overheated. it is generally used as an ingredient in food processing. additional requirements exist for labeling baker's honey, including that it may not be sold labeled simply as "honey". grading countries have differing standards for grading honey. in the us, honey grading is performed voluntarily based upon usda standards. usda offers inspection and grading "as on-line (in-plant) or lot inspection...upon application, on a fee-for-service basis." honey is graded based upon a number of factors, including water content, flavor and aroma, absence of defects, and clarity. honey is also classified by color, though it is not a factor in the grading scale. the honey grade scale is: grade soluble solids flavor and aroma absence of defects clarity a ≥ 81.4% good—"has a good, normal flavor and aroma for the predominant floral source or, when blended, a good flavor for the blend of floral sources and the honey is free from caramelized flavor or objectionable flavor caused by fermentation, smoke, chemicals, or other causes with the exception of the predominant floral source" practically free—"contains practically no defects that affect the appearance or edibility of the product" clear—"may contain air bubbles which do not materially affect the appearance of the product and may contain a trace of pollen grains or other finely divided particles of suspended material which do not affect the appearance of the product" b ≥ 81.4% reasonably good—"has a reasonably good, normal flavor and aroma for the predominant floral source or, when blended, a reasonably good flavor for the blend of floral sources and the honey is practically free from caramelized flavor and is free from objectionable flavor caused by fermentation, smoke, chemicals, or other causes with the exception of the predominant floral source" reasonably free—"may contain defects which do not materially affect the appearance or edibility of the product" reasonably clear—"may contain air bubbles, pollen grains, or other finely divided particles of suspended material which do not materially affect the appearance of the product" c ≥ 80.0% fairly good—"has a fairly good, normal flavor and aroma for the predominant floral source or, when blended, a fairly good flavor for the blend of floral sources and the honey is reasonably free from caramelized flavor and is free from objectionable flavor caused by fermentation, smoke, chemicals, or other causes with the exception of the predominant floral source" fairly free—"may contain defects which do not seriously affect the appearance or edibility of the product" fairly clear—"may contain air bubbles, pollen grains, or other finely divided particles of suspended material which do not seriously affect the appearance of the product" substandard fails grade c fails grade c fails grade c fails grade c india certifies honey grades based on additional factors, such as the fiehe's test, and other empirical measurements. indicators of quality high-quality honey can be distinguished by fragrance, taste, and consistency.