2.12.1 Liquid honey
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Some honeys remain in a liquid state naturally, if they have a low glucose content and a glucose to water ratio of less than 1.8 (e.g. honey from black locust, chestnut and tupelo), a high water content or if they are kept constantly at a temperature of more than 25 0C (or less than 5 0C). It must be remembered that high water content and temperatures above 25 0C are not desirable for the quality of honey.
If it is necessary to keep honey liquid for extended periods of time, some special measures have to be taken to ensure such liquidity. The following discussion is intended to give some practical hints for preventing crystallization.
In order to liquify honey which has already crystallized or has started to crystallize, the honey is most commonly heated ~ust prior to sale) to 40 - 500C until all the crystals are dissolved. The dissolution of the crystals is more commonly referred to as "melting" by beekeepers. It is more practical to melt the honey prior to bottling, but it is quicker after bottling when complete melting of all crystals is easier to control.
The length of time that honey remains liquid after such melting is variable and depends, as with unprocessed honey, on its composition and the storage temperature. Once heated honey recrystallizes, it should not be melted again, since the much larger crystals now require more heat to melt them. The degradation caused by a single treatment like this, including the damage caused by heating honey for 24 hrs at 400C and the time required to melt it completely, is far less than that produced by prolonged storage at a temperature above 250C (see Table 2.11).
For industrial processing, relatively complex techniques (not just melting the crystals) are employed to delay re-crystallization. As a first step honeys are selected and mixed in such a way that the final product shows constant colour and flavour characteristics and a relatively low glucose content. For that reason honeys with high glucose content such as rape, sunflower and composite honey are generally excluded.
The following processing method was suggested by Gonnet (1977) for honeys or honey mixtures with a glucose content of less than 35 % and a glucose to water ratio of less than 2 (see Table 2.13 for a summary of the equipment needed). Honey is partially melted in a hot room and transferred to a heated vat where it is mixed until almost all crystals have dissolved. It is then strained to eliminate contamination by foreign debris and pasteurized at 780C for 5-7 minutes using a fine-leaved heat exchanger.
Equipment of a typical processing plant for bottling liquid or
crystallized honey (* with pasteurization).
|Melting room||Controllable temperature at 35-50°C for warming, melting and softening of honey in barrels and jars|
|Pumps||Moving honey from one tank or machine to another, adapted for liquid and/or crystallized honey|
|Jacketed tank (#1)||receiving "dirty" honey direct from the melting room to complete melting, settling, mixing and heating|
|Strainer||Eliminating visible impurities|
|Heat exchanger (#1)*||Quickly heating honey to 65°C for honey to be recrystallized or to 78°C for liquefaction with pasteurization|
|Filter*||Removing all or part of the microscopic impurities|
|Heat exchanger (#2)*||Quickly cooling the honey|
|Jacketed Tank (#2)||Receiving "clean" honey, cooling it to 30°C and mixing it with seeds for controlled crystallization; mixing honey during crystallization at 20°C, or receiving honey previously cleaned and crystallized directly from the melting room, where it has been softened by heating to not more than 30°C.|
|Storage tank||Receiving warm liquid honey from the strainer or heat exchanger for bottling|
|Bottling machine||Bottling various size containers with liquid or crystallized honey|
Together with the next step, this heating is the most important, since high temperature, besides destroying yeasts, also melts the micro-crystals responsible for starting (seeding) re-crystallization. In the next step, ultra-fine filtration under pressure, using different micropore filters or diatomaceous earth, removes very fine particles such as pollen, bacteria, etc., which might serve as seeds for restarting crystallization. Subsequently, honey passes through similar heat exchangers which cool it to bottling temperature (570C according to the American school (Townsend, 1975) -or 35 °C according to the European school (Gonnet, 1977)). It is then bottled, preferably in dry-cleaned containers. An extra step which can further prolong the liquid state is quick cooling of the bottled product and storage for S weeks at 00C before releasing it onto the market. After this treatment liquid storage is prolonged, but crystallisation can still occur.
This kind of filtration is a normal and accepted practice in the USA, Canada and various Latin American countries and is preferred, because in addition to a longer liquid shelf-life, it gives a clearer and brighter product. As already mentioned, in European countries such complete filtration which eliminates any microscopical particles, is forbidden. It deprives honey of valuable substances such as pollen and makes it impossible to identify its botanical and geographical origin by means of pollen analysis. It also makes impossible the identification of other microscopic elements normally found in honey. Thus honey destined to be marketed in EEC member countries cannot be filtered this way.2.12.2 Creamed honey
As an alternative to liquid honey, techniques have been developed to guide the natural crystallization of honey towards completely crystallized, stable and homogeneous end products with a pleasant appearance, creamy consistency and good reception by most consumers. The advantage of this method is that it does not require any treatment which would alter by any means the fragile and beneficial characteristics of the honey. In addition, these methods are also well suited for small scale production and become more complicated only with an increase in quantity.
The basic principle consists of accelerating the natural tendency to crystallize by the addition of a small quantity of already crystallized honey. This method can be used with all honeys which show a tendency to crystallize either rapidly, slowly or incompletely. In the most simple method, liquid honey (naturally liquid or liquified) is mixed with completely crystallized honey, preferably containing very fine crystals, at a ratio of 9 to 1. The mixture should be warmed to only 24 to 280C in order to allow easier mixing and to ensure that none of the crystals are melting. No air bubbles should be included during this mixing. Prior to bottling, the honey is left to settle for a few hours to allow any air bubbles to escape. After bottling, the containers are kept as close to 140C as possible. Depending on the moisture content, crystallization is complete in about 10-14 days and a fine crystal honey of more or less solid consistency is obtained.
The major inconvenience of this method is the excessive hardness reached by low moisture honeys due to the formation of transversal crystals, special agglomerations. To avoid such occurrences, potentially unpleasant for the consumer, a method has to be chosen which allows the separation of each individual crystal and which thus gives the honey a creamy consistency. One aesthetic problem with this type of preparation is the formation of whitish blooms on the surface and inside enclosed air bubbles, due to the surface evaporation of water and drying of glucose crystals.
One method of softening this crystallized honey consists of two distinct phases. In the first phase the guided crystallization is conducted as described previously. However, the honey (seeded with fine crystals) is left to crystallize for approximately 10 days in larger containers (25 to 300 kg) at a temperature of 140C. Instead of bottling, the containers are then placed into a warm room at 28 to 300C until the honey has become a little softer. During this second phase, with the honey always below its melting point, a homogenizer or mixer is introduced into the softened honey in order to break up the crystals (Gonnet, 1985 and 1986). Once stirred, it can be bottled. Alternatively, even the simple warming in the heating room and subsequent bottling will give satisfactory results, since even this small movement of the softened honey will break up the crystals. The critical point to watch is the temperature during softening and stirring, which should always remain below 280C. If the crystals start melting the whole process will fail.
In another method, the seeded honey is stirred at a temperature at which the crystals readily grow (near 200C). The same water-jacketed vats for heating honey can be used cooling with cold water. Agitation accelerates crystal formation considerably and helps formation of smaller crystals. After two to three days, crystallization is complete and honey can be bottled, possibly raising the temperature a few degrees to ease the flow.
The difficulty here is to stir a cold and therefore very viscous mass of honey. This not only requires considerable mechanical force, but also carries a risk of incorporating air and creating a foam. It is therefore necessary to work with sufficiently powerful motors and a slowly rotating propeller (a few rotations per minute) which should remain immersed in the honey. In the largest industrial operations, in addition to the standard mixing devices, a continuous cooling and scraping system is employed for homogenization. For small quantities not exceeding 100 kg at a time, it is possible to do everything manually and stir once or twice a day with a long wooden paddle.
Creamed honeys, produced by one of the last two processes, will always have a creamy consistency more or less fluid, depending on the water content. The main disadvantage of these preparations is their instability at warm temperatures. If stored at temperatures above 20 0C for many months the crystals tend to precipitate on the bottom of containers leaving a more or less thick, liquid layer at the surface. This separation of liquid and crystalline phases (or partial reliquefaction) is more rapid in honeys with a higher moisture content and at temperatures close to or above 25 °C. In temperate climates with honeys averaging less than 18% moisture and low storage temperatures (favouring crystallization) guided crystallization appears a very advantageous and profitable process, as the profusion of the Dyce process in Canada indicates (Dyce, 1975).
A problem common to all these processes is the choice of seed honey, which has to have very fine crystals itself. Some honeys naturally form very small crystals. However, if no such honey is available, a normal, crystallized honey can be milled by passing it through a meat grinder or grinding it with a pestle and mortar to reduce the size of the crystals. If creamed honeys can be found (for example in a shop) they can be used as a starter. Small quantities are mixed with liquid honey and left to crystallize for ten days at 140C with occasional stirring. This is then used as seed for a larger batch, always mixing seed honey with liquid honey at the ratio of 1:9 i.e. 1 kg of seed honey to 9 kg of liquid honey. This process can be repeated until the final, desired batch size is reached. When bottling, sufficient crystallized honey should be retained to seed the next batch.
For the manipulation of cold and therefore very viscous honey, the mixer, pump and bottling machine have to be very strong. The facilities and structures necessary for cooling during processing and storage are expensive. Smaller scale manual operations do not have these difficulties and can produce an attractive product cheaply and without expensive equipment, if ambient temperatures are not too high. Lastly, if the honey to be processed has a high moisture content and there is a possibility of fermentation, it should be pasteurized at 65 0C for 5 to 10 minutes before crystallization. In this case, the seed honey has to be free of yeasts.2.12.3 Comb honey
A particular type of colony management is required for honey destined to be sold in complete comb. Apart from being the most traditional form, it can also be sold to a market which rarely has access to this most basic of all bee products. Its implied guarantee of purity and freshness is appreciated by many consumers. Special production techniques have been developed to produce a clean, fresh-looking piece of section, cut-comb or chunk honey, which is easy to ship, handle and retail. In any case, these products require special care during preparation and do not favour long transportation at warm ambient temperatures, nor long-term storage.
Section comb honey is a small section of completely sealed comb built of virgin (new) beeswax, preferably with light-coloured honey which remains liquid until consumed. Round, square or hexagonal sections with prefabricated wood or plastic frames are given to the colonies with a very thin foundation sheet. The specially prepared colony fills up the sections with comb and honey which is directly packaged in an attractive clear container (plastic wrap, box with clear window etc) to protect the contents from contamination, moisture and breakage. Special frames and packaging material are sold by most beekeeping suppliers, but forms, construction and quality vary from country to country (see Figure 2.16).
Regular beekeeping texts do not always cover section comb honey production, because it requires more intensive management and better planning. A special treatment of the subject is given in a book by Morse (1978) and in the new edition of the Hive and Honeybee (Graham, 1992). Short articles, such as Taber (1991), occur occasionally in the various beekeeping journals.
For special attractions, some beekeepers have produced comb inside narrow mouthed bottles, by providing a guide and enticing bees to build comb and store honey inside the bottles themselves.
Cut comb honey can be produced in regular frames or topbar hives. If foundation sheets are used they should be particularly thin and no wires or other reinforcing materials should be incorporated into the comb. Pieces are carefully cut according to the package shape and size and are left on a wire rack to drain the honey from the cut cells, taking care to keep bees away. Once dry, they can be packaged like section comb honey in clear protective containers. Extra care needs to be taken not to break any sealed cells or smear honey over them because it will look unattractive later on. If left in the sun even momentarily, wax cappings will become transparent and the comb will break easily with the slightest movement. All other conditions, such as light-coloured honey, cold storage and avoiding rough transportation and handling are the same as for section comb honey.
Smaller comb pieces can also be packed inside jars, which may then be filled with liquid honey. Ideally the comb honey and the liquid honey will be of the same light clear colour. Each jar should have only one cleanly cut "chunk" and honey should not crystallize before consumption.2.12.4 Mead
The quality and taste of mead depends, apart from fermentation control and the quality of the various ingredients, mostly on the characteristics and taste of the selected honey.
The first production phase consists of the preparation of the must. A good quality honey with the desired flavour should be selected and a good water supply obtained. The water can influence the mead' 5 flavour, particularly since public water supplies often have all kinds of minerals, chemicals and other ingredients" in them. Clean and soft rain or well water are best, but should be boiled first. The honey has to be dissolved in the water. larger quantities the honey should be pre-mixed in a small amount of warm water.
The quantities to be used depend on the water content of the honey and the desired sweetness and alcohol content of the mead. In general, one considers 2.3 kg of honey per 100 litres of water for each alcohol grade (% by volume) in the final product. More precisely, one has to add 21 % sugar solids (measuring only the sugar content of the honey without water) to obtain a dry mead with 12% (by volume) alcohol. Increasing the sugar solids to 25 % leads to a final alcohol content of 14-15 %. Further additions of sugar leads to residual sugar in the final product and therefore a sweeter mead.
Pasteurization is generally not necessary prior to fermentation but filtration to remove any solid particles is recommended. One school of mead makers does however recommend sterilizing or pasteurizing the must before adding the selected yeasts. This can be achieved either by heating to 780C for 7 minutes or by adding tablets that produce sulphur dioxide, as used in regular wine making. These tablets are also known as bisulphite or "Campden" tablets. The sulphur dioxide gas will escape and will not flavour the mead. These same tablets can be used to disinfect bottles, siphons, corks and funnels.
Minerals and salts are added to the cooled must as yeast nutrients (urea, ammonium phosphate, cream of tartar, tartaric and citric acids). The acids are supposed to improve the taste and prevent growth of undesirable microorganisms. Various nutrient combinations are listed in the detailed recipes below. If 50% of the water is substituted with fruit juice, none of these additives are necessary, since the fruit juice provides both nutrients and the right yeasts. Some countries do not allow the addition of fruit juices to mead.
An adequate quantity (0.5 to 2%) of selected, active, acid resistant champagne yeasts or brewers yeasts, but not bread yeasts, are added. The choice of yeast influences the final flavour, but selection is more important in order to have complete and uninterrupted fermentation. An actively growing yeast solution should be prepared for larger batches (see second recipe below). For small batches, the yeasts can be added directly to the must.
In order to speed up the fermenting process in mead making, Qureshi and Tamhane (1985) immobilized yeast cells in calcium alginate cells. Improvements in taste are said to be obtained by flash heating the must, before adding the yeast, or 30 seconds to 1020C and instant cooling to 70C (Kime et al., 1991).
Fermentation has to take place in the absence of air (oxygen) in appropriate containers, preferably made from ceramics, stainless steel or glass or in wooden barrels. To exclude outside air a special fermentation lock is placed in the opening of the container, so that gas from the fermentation can exit, but outside air cannot enter. This is important, particularly towards the end of fermentation when less gas is produced inside. If too much oxygen enters, the mead will turn into vinegar. The simplest method, but not a completely safe one, is to place a cotton ball in the opening of the container or in a perforation of the stopper. Another improvisation is a plastic hose leading from the same perforated stopper into a glass of water, with the end of the hose always submerged in water. The glass always has to be kept at a lower level than the end of the tube in the stopper as a precaution against sucking the seal water back into the fermentation vessel.
Figure 2.16: a) Section comb honey, stored by bees directly in special round or square clear plastic sections. b) Decorative wooden sections are prepared with a thin foundation sheet and placed in supers in lieu of frames and in the same manner as plastic sections.
During fermentation the must should be maintained at a constant temperature of 20° to 25 0C (18 0C according to Morse and Steinkraus, 1975) but not exceeding 28 0C. The exact temperature is not absolutely critical since fermentation will also take place at other temperatures but at different speeds. The longer the fermentation, the greater the risk of contamination by other bacteria or yeasts will become. At higher temperatures fermentation will be faster, but will produce less alcohol. At lower temperatures fermentation will become progressively slower and eventually stops.
After 2 to 3 days of fermentation, an oxygenation of the mead by decanting it into another container may be beneficial but not necessarily so. Once fermentation has slowed down however, decanting is beneficial to prevent the mead from becoming bitter from the dead yeast accumulated at the bottom of the container. Otherwise, the must is left undisturbed for approximately one month or until no more gas exits from the fermentation lock. The liquid is then carefully poured or syphoned off with a hose, without disturbing the sediment. This decanting is not enough to clarify a mead made from only honey. For complete clarification, extremely fine filtration or the addition of precipitating agents such as tannins (2.5 g dissolved in alcohol, per 100 litres), bentonite (100 g/l00 1) colloidal protein solutions or egg white beaten very well (the whites from 2 eggs for 100 1) is necessary. After a few days the liquid is syphoned off again or filtered. Alternatively, boiling the must prior to fermentation will precipitate most of the proteins responsible for clouding mead (Berthold, 1988a) but will also eliminate most of the honey aroma.
Finally, the mead has to be aged to develop its flavour. The use of oak barrels is best, but aging in bottles is possible. Different preparations reach maturity at different ages (6 months to 3 years) but at least 18 months should be considered. For commercial operations the addition of a preservative like potassium sorbate (15 - 20 gibO 1) may be used or the mead may be pasteurized immediately prior to bottling.
For the production of vinegar it would be advantageous to start the mead with a must of half the concentration of honey, but the same amount of nutrients. After one month of alcoholic fermentation (in the absence of air) a culture of vinegar bacteria (Acetobacter aceti) are added. Alternatively, a little of ready-made vinegar may be added, but not commercial, pasteurized vinegar. The containers are then left open to the air, but should be covered to prevent dust and other debris from entering. At 20° to 25°C and with sufficient bacteria, the process can be completed in just a few days, but would more likely take 1 to 9 months. After occasional tasting or acid testing to determine the point of maturity, the vinegar can be bottled for sale or personal consumption. A level of 5 % acid (by volume) is considered mature.
The following is a step by step description of the basic mead making process as adapted from Steinkraus and Morse (1966) for a dry (non-sweet) mead from white clover honey with a final alcohol content of about 12% by volume. This approach is rather "high-tech" and nutrients may be hard to get, but it demonstrates the necessary points of production control. For most productions, the nutrients can be simplified (see following recipes).
|5.000 g||Citric acid (or 2.528 g citric acid and 2.468 g of sodium citrate, which require less pH adjustment)|
|1.229 g||Ammonium sulphate|
|0.502 g||Potassium phosphate (K2PO4)|
|0.185 g||Magnesium chloride|
|52.80 mg||Sodium hydrogen sulphate|
|5.28 mg||Thiamine (vitamin B1)|
|2.64 mg||Calcium pantothenate|
|0.26 mg||Pyridoxine (vitamin B6)|
|0.013 mg||Biotin (vitamin H)|
- Honey is diluted to 21 % solids with water. If crystallized, the honey is heated to 60-65 0C to facilitate dissolution;
- all of the above nutrients are added to the diluted honey;
- the pH is adjusted to 3.7-4.0 with sodium hydroxide or hydrochloric acid;
- when cooled to about 270C, the 150 litre batch is placed in a 200 litre oak barrel;
- the batch is inoculated with 0.5% by volume of active yeast culture and sealed with a fermentation lock (}or preparation of such a growing yeast culture see the second recipe);
the mead is maintained at 18 0C during fermentation;
- after 6 months of aging it is decanted and filtered through Celite 503 or similar filter-aid, to remove yeasts;
- total acidity is adjusted to 0.6% with citric or tartaric acid;
- the mead is pasteurized at 63 0C for 5 minutes and bottled while hot.
Other possible modifications such as decantation, pasteurization, disinfection, nutrient alternatives, filtration, clarification, fermentation temperatures and aging have already been discussed.
2) Gonnet et al., (1988) recommended the preparation of a starter culture of yeast particularly for larger batches. The following proportions are for such a starter batch. The final must therefore consists of: 1) a sugar and water mix, at a ratio according to previously mentioned criteria; 2) nutrients added in the same quantities per litre as given for the starter batch below and 3) the yeast starter batch at 2% by volume of the total must.
Ingredients for the starter batch:
|1.1 kg||Selected yeasts|
|29.5||Nutrient salt mix|
The honey is dissolved in the water and at 25 0C the nutrient salts and yeast are added. Mix well and leave for three days at 25 0C in a container sealed with a fermentation lock. After that, once stirred well, it can be added to the final must at 2% by volume.
Nuteients per litre of must or starter batch:
|0.250 g||Diammonium phosphate|
|0.250 g||Potassium bitartaric (cream of tartar)|
|1.875 g||Trataric acid (or 1.750 g of citric acid)|
|0.050 g||Potassium metaisulphite|
|0.250 g||Yeast extract|
3) Soldati and Piazza (1985, unpublished communication) following nutrients per litre of must (and many other ingredients with no apparent difference due to use of lower describe the use of the variations of these basic or higher concentrations):
|2.00 mg||Ammonium sulphate||
|750 mg||Ammoinum carbonate|
|0.75 mg||Potassium metabisulphite||1000 mg||Ammonium phosphate|
|1.00 mg||Citric acid||500 mg||Citric acid|
|0.25 mg||Vitamin complex (unspecidfied)|
They start with a 1.3 mixture of honey and water and a Baume' (a unit to measure sugar content) reading of 13.5° to 14.5°. After the initial pasteurization and addition of the nutrients, 10% of the must is used for a starter batch to which the selected yeasts are added. One to two days later when the yeasts are fully active, the starter batch is added to the rest of the must. when the must has reached a Baume' of 0.1°, for a dry mead (or earlier if so desired), fermentation is interrupted by transferring the liquid (without sediment) into another container in which the (second) fermentation continues for another 15 to 30 days. At this point the mead is clearer and can be filtered and bottled. For storage reasons, the mead should have at least 10% alcohol and not less than 3.5 g/l acidity, measured as tartaric acid.
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