Expert Advice on Making Donuts
Using Key Blends Concentrates
The following is general recommendations of making yeast donuts using Key Blends concentrates. Production methods such as table cut, pressure cut or stamper can significantly alter the requirements of yeast donut handling. Key Blends are donut experts. We have significant experience in all of these methods and we provide training to our customers in the optimum methods for their plants.
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Remember, Yeast Raised Donuts are not cakes, but are living systems due the yeast fermenting the dough. The fermentation is vital to the finished yeast donut. Always trust fermentation. It is extremely rare for any production problems to originate from excess fermentation. It is better to think of a yeast donut as a fried bread product than a cake item.
There is usually more than one way to solve any one problem in yeast donuts. However, there is usually only one way that will solve the problem without creating new problems
Yeast must ferment the dough in order to produce a satisfactory donut. NEVER underestimate the importance of fermentation in yeast donuts. The fermentation process is a complex series of reactions that produces carbon dioxide, alcohol, acids and other chemicals that contribute to the softness and flavor of the donut. The pH level of the dough drops as the fermentation continues. These chemicals and the yeast activity mellow the wheat gluten. The result is a far superior dough that has better volume, shelf life, and taste.
When yeast is first added to the dough, it is still in a relatively dormant state induced by the final stages of its manufacturing process. This is especially true if dried yeast is being used. Proof times are very short when compared to bread and it is vital to take advantage of every opportunity to gain fermentation during this short process. If no pre-fermented dough (Scrap) or brew is added to the dough, the yeast activity is relatively low. The semi-dormant yeast will still produce carbon dioxide to leaven the dough but the other by-products will not be produced giving the dough the strength that is needed. Low fermentation equals a young dough. Young doughs produce firmer/dryer donuts with a shorter shelf life.
High sugar levels and salt will retard fermentation, high water levels speed up fermentation. Since these factors can not be changed, the only good way to get adequate fermentation is by controlling temperature, time and yeast levels. Low levels of sugar in the yeast donut dough act as food for yeast and sugar will speed up the fermentation. However, at the higher sugar levels, the osmotic pressure exerted by the sugar will slow down the yeast. In a lean yeast donut sugar will speed up fermentation, but in a rich dough, the sugar will slow it down. It is vital to be aware of this difference.
The goal of fermentation is matching the time when the yeast is producing the maximum amount of carbon dioxide when the gluten is the strongest. This will produce a yeast donut with the best volume.
Age and Development
Age or fermentation can come from three sources, biochemical, chemical, and mechanical development. Biochemical age is produced by the yeast fermentation. The longer the donut dough and the flour are exposed to fermentation, the older the donut dough is. This biochemical fermentation is due to the activity of the yeast forming a variety of acids and alcohols that interact with the flour. Chemical age is produced by additives added to the donut dough such as L-cysteine, acids, enzymes etc, that react with the flour and/or enhance the yeast environment . Mechanical age is produced by mixing. A slightly over mixed donut dough will act like an old dough to a limited degree. The opposite will happen to a slightly under mixed dough.
Using these principles, fermentation, mixing and formulation a correct formula and mixing time will result in the optimal parameters for yeast donuts. For example, if your doughs are acting a little old, reduce mix time, fermentation or both.
Scrap un-fried donut dough and brew are the two primary sources of pre-ferment in yeast donuts. The flour from the brew is only 30% of the total flour in the dough. In other words, only a small portion of the flour in the final dough has been fermented when only brew is used. The scrap dough will add more fermented flour as well as some very active yeast.
Two things to remember are:
- to never use scrap fresh off the table
- never use too much very old scrap.
Very old donut scrap is broken down and is wet. Very old scrap will ruin any donut dough. It is best to fill the scrap buckets 2/3 of the way full. When the scrap has fermented to the point where the bucket is full, the scrap has enough fermentation. Scrap that is 1 to 2 hours old is ideal.
Old scrap that is too old will be over gassed bucky, wet and sticky. Once the dough gets to the point where it gets very warm (approximately 120F) The yeast will begin to die releasing glutathione which is a powerful reducing agent. The glutathione will begin to break down the gluten releasing the water resulting in a very wet sticky dough. Never used this type of scrap in a dough. As a rule, it is usually better to trash the old scrap rather than use it.
The amount of scrap and the amount of fermentation the scrap has received will drastically effect on the mix times. In other words, the more the gluten has been exposed to fermentation before mixing to the lower the amount of time is needed to develop the dough in the mixer. Adding scrap to the beginning of the mix will reduce the mix time as well since the new flour will be exposed to the by-products of fermentation during the mixing.
Floor time is the time the donut dough needs to relax after the mixing process. The mixing process puts significant mechanical abuse on the dough. The donut dough needs to recover from the abuse before it is allowed to continue. There is not a right time or a wrong time but the dough and the final product must be observed to determine the proper floor time. Floor time also serves as critical additional fermentation. Remember the yeast added to the dough takes over 45 minutes to become fully active.
A freshly mixed dough will be softer and highly extensible. A dough that has received a little floor time will start to get spongy and will break cleanly when stretched. A fully matured dough will be dry and very mellow, it will break clean and sharp with minimal elasticity.
Floor time is related to mixing. If a donut dough is over mixed, it requires more floor time for the gluten to recover. An under mixed dough will require less floor time due to less mechanical abuse.
In yeast donuts, a dough with inadequate floor time will exhibit the tendency to have the beginning of the dough to be sticky. This results in misshaped donuts. The first donuts at the fryer will also be small with the donuts getting bigger as the dough experiences more fermentation.
Excessive floor time can also cause problems. Excessive gassing will cause problems during extrusion. The end of the dough may be too old.
Floor time tolerance also varies with production method.
Yeast Donut Mixing
There are basically two factors to be considered in the mixing of the donut dough, temperature and gluten development.
Mix times are rarely constant. The mix operator must feel each dough and adjust his mix times slightly to give the same amount of gluten development. As stated earlier, biochemical, chemical, and mechanical development are all interrelated. If the scrap added to the dough is older or more is used, the dough will develop faster in the mixer. The opposite is true as well. The mixer must be aware of this. Consistent scaling and fermentation will result in consistent mix times. If your mix times are inconsistent you should evaluate your fermentation procedures.
Temperature is a critical point in the fermentation of the dough. As a rule of thumb, a rise in 10F will result in twice the rate of the fermentation reaction up to 100 to 105F. This is a 10% increase for every degree. If the donut doughs vary in temperature, the final donut will never be consistent since the proof time will not vary 10% per degree change. Donut doughs must be consistently mixed to the proper temperature and the temperature should not vary between doughs.
Proofing is the final fermentation stage. If everything is correct during the proofing stage the donut dough will reach its maximum strength during the latter stages of the proof when the yeast activity is at its greatest. This will result in a donut with good volume with good spread.
The first zone of the proofer should be slightly more humid allowing the donut to spread more. The donut should feel velvety soft but never wet and sticky. The second zone should always be slightly dryer. This allows the skin of the donut to dry out slightly. This helps with gas retention and strength. The proofer should be monitored frequently to determine if the conditions are right. Slight variations in the dough and in the fermentation will require changes in the dry and wet bulb settings.
Blisters are caused by excessive dryness in the proofer. A very dry skin will form a skin that moisture can no escape during the first stages of frying. The rapid release of steam will form a pocket (blister) during the first 10 seconds in the fryer. I have never seen dockers, needle wheels and the like actually work in production. The best way to eliminate blisters is by increasing water in the dough and/or moisture in the proofer. A quick way to test this is to spray the donuts with water on the side that is getting the blister (after proofing) and watch the results.
The best way to judge the proof is by final product. The internal temperature can also be used to determine the degree of proof. The internal temperature will vary from process to process and product to product. However, it should be fairly constant in your operation. A donut with a normal proof time of approximately 30 minutes should reach an internal temperature of 105F plus or minus 3F at the end of the proof. Short proof times require higher internal temperatures of 110F and higher.
Too low an internal temperature can result in raw spots in the finished product. The fryer can not be expected to cook out the donut if it is too cold before entering the fryer
Never proof by the dry bulb and wet bulb settings. Always feel the donuts and observe the product in the fryer. Compare the beginning of the doughs to the ends before making adjustments. Proofers with higher air velocities will need a wetter proofer and low-velocity proofers need a drier proofer.
Another fault caused by incorrect proofing is white spots on the surface of shell donuts. White spots on donut surface can be caused by too wet a proofer. When the donuts get sticky in the proofer, they stick to the tray and will get concave bottoms. This will result in white spots. Do not proof wet. A drier box is critical to getting a good donut.
This advice may sound contradicting. But the most important thing is to feel the product and adjust from experience.
The fryer is the point where all decisions concerning fermentation, mix time, mix temperature, floor time, and proof time are made. Never bake by numbers always observe the final product and make adjustments.
Most donuts will fry in 90 to 110 seconds at 375F. Never increase the fry time to increase the fat absorption. If the fat is too low, there is a problem in formulation. Always fry at the lowest temperature possible. Newer palm based donut fry shortenings do not have the stability of partially hydrogenated soy shortenings. Lower donut fryer temperatures help maintain donut fry shortening quality.
Donut Production Critical Control Points
- Set temperature of brew determines rate of fermentation. Higher temperatures speed up fermentation drastically. This temperature should be recorded for every brew. This is not the temperature of the water, it is the temperature of the brew after it has been set.
- Rise temperature is final temperature set temperature. This is an indication of the amount of fermentation. The fermentation activity of the yeast creates heat. This temperature should be recorded for every brew.
- Ferment Time Increasing and decreasing the total ferment time will change the age of the brew.
- TTA and pH Measure at least once a day. The value should be compared to the temperature rise. There should be consistency between the values or the set temperature and/or the ferment time should be adjusted
- The amount of scrap should not vary as this will alter the age of the dough. Scrap is very important in order to obtain the desired level of age as the level is not high enough to depend on it exclusively.
- Ferment time on scrap Fresh scrap should never be used. Fresh scrap has practically no value. also, allow the scrap to proof up before use. Very old burnt out scrap should be added only in small quantities as this will have a negative effect on the product.
- Ratio of age of scrap and amount of scrap The older the scrap is, the less is needed. The younger the scrap is the more that is needed. The two are directly related.
Donut Dough Mixing
- Mixing times will vary. Each dough must be evaluated by the mixer. The age of the brew and the scrap will alter the mix times. Changes in the flour will also alter the mix time. It is vital to monitor this closely.
- The final temperature will determine the rate of proof. The final product should determine the dough temperature. The final mix temperature should be recorded for each dough.
- Degree of development Since there is a possibility of changes in the brew, scrap, and flour, the doughs must be evaluated for mix development. Elasticity and extensibility of the doughs must be evaluated.
Donut Dough Floor Time
- Floor time is related to the amount of development from mechanical, biochemical and chemical sources. The more the dough is over developed the longer the floor time must be to allow the dough to recover. Underdeveloped doughs need less time. If there is consistency in the development of the doughs there will be consistency in floor times.
- Temperature and humidity of the first zone The first zone of the donut proofer should be moister than the second zone. Donuts should be evaluated in the box several times per shift to determine if the conditions are correct. The donuts should feel velvet like and not dry. The donuts should not feel sticky. This allows the donut to flow on the shelf without sticking to the shelf.
- Temperature and humidity of the second zone The second zone needs to be dryer to allow a skin to form. The skin will give the donut support and help retain gasses during frying. If blisters are forming, the box is too dry. Once again, this should be evaluated several times per shift.
- Internal temperature of donut leaving proofer The internal temperature will determine the degree of proof. Proof box temperatures and dough temperatures need to be adjusted to optimize final product characteristics. Optimal temperature can vary slightly but for your current product, it should be 105
Donut Fat Absorption
- Yeast donut fat absorption is an important quality parameter that should be monitored. Low-fat levels produce a donut that has a shorter shelf life and will have glazes and icings that break down more quickly. Too high a fat level will produce a donut that is more expensive and will have a greasy mouthfeel.
- Yeast donut fat levels (% of fat of the finished donut with no icings or glazes) should range from 24% to 33%. Type of donut being produced, size, shape and desired shelf life and eating characteristics will determine the fat level.
- The most important factor that will alter the fat level is the shortening added to the dough. As more shortening is added the fat level goes up. A donut with more fat in the dough will be more tender and will absorb more fat from the fryer. A yeast donut ring dough (honey dip) will have about 6 to 10% fat based on flour or approximately <5% fat and a very rich fried honey bun will have 20% fat based on flour or approximately 9.5% fat. The higher fat product will absorb more fat from the fryer resulting in a finished fat level that is up to 10% higher than the very lean product.
- Flour protein will change the fat absorption. Gluten will form a film that will block the fat from entering the donut. The higher the level of protein, and the higher the strength, the more that the gluten will block the fat. There is a significant difference between the varieties of flours (spring wheat vs. winter wheat, clear flours vs. normal extractions) Spring wheat flour has the highest level of strong proteins. Clear flours are high in protein, but the quality is very low. Do not use clear flours in donuts.
- Sugar acts a tenderizer and will increase fat absorption. Higher sugar levels will weaken the gluten and will allow more fat to be absorbed. The osmotic pressure of the sugar will draw water from the gluten. This has 2 effects. First, the dough will appear to be wetter (softer) and the fermentation will slow down as the levels increase.
- As you can see, the function of the ingredient influences the fat absorption of the finished donut. In addition, the dilution effect is another factor. As more shortening and sugar and other nonstrengthening ingredients are added the more the strengthening ingredients are diluted. The addition of sugar and shortening can have quite dramatic effects on the finished fat level
Controlling Mold Growth in donuts
There are several ways to control the growth of mold on yeast donuts depending on what is causing the donut to go moldy.
The most important aspect is bakery sanitation. Unless the bakery is clean and mold-free, no method will guarantee mold-free shelf life. Quaternary ammonia products can be applied at 200 ppm to sanitize the surfaces of the bakery. Special attention needs to be applied to 'wet areas' such as bowl cleaning areas.
Increasing preservatives to compensate for poor sanitation will not work as calcium propionate are not generally cidal at the level used in foods. They, therefore, will not reduce existing yeast or mold contamination, but instead retard further growth of organisms already present, provided the degree of contamination is not too high. Products that have already spoiled or foods prepared under poor sanitary conditions will not benefit from the use of this preservative.
Adequate and proper preservatives are also key to proper mold inhibition. Calcium propionate is the only inhibitor that will work in a yeast raised dough. All other preservatives will inhibit the yeast and prevent proper fermentation. Excessive levels of calcium propionate will also inhibit the yeast and will not help. The glaze can contain much stronger preservatives such as potassium sorbate and sorbic acid. The glaze must contain at least 1/10 of 1% of potassium sorbate or sorbic acid. Remember that if you use these preservatives at high levels, do not use reclaimed glaze as sugar, it will kill the yeast.
The last factor is equally in importance and that is fermentation. Increasing the fermentation will allow the donut to cook out better. Large donuts or jumbo donuts need to be fried out completely. Raw spots in the center of the donut will cause mold to grow in the center of the donut. Sometimes donuts that are doughy in the center go sour or moldy in the center. Whenever this happens, increase fermentation. This is a strong indication that the proof box is too cold, increase the temperature of the box. It would also be helpful to increase dough temperature, increase amount of scrap dough and increase the yeast level.
The dough must be properly fermented to cook out the donuts.
Critical Ingredients in Donuts
No technical discussion on yeast raised donuts can be complete without a discussion on ingredients. The most important ingredient is flour.
Yeast donuts are made from wheat flour. Wheat flour is the only flour that contains gluten which is the protein responsible for the cell formation. All other flours (rye, barley, corn etc) do not contain gluten.
Types of Wheat
There are many types of wheat (soft wheat, hard wheat, red wheat, white wheat). Soft wheats are low in protein and the proteins are weak. Soft wheats are used to produce cake and pastry flours. Hard wheats are higher in protein and the proteins are stronger. Hard wheats are used to produce bread flours. Yeast donuts are made with hard wheat flours.
Spring Wheat vs. Winter Wheat
There are basically two types of hard wheats, spring, and winter. Normally a Hard/soft winter wheat flour blend is used in table cut donuts. In some regions, a winter/spring blend is used. A yeast donut should be tender. Pressure cut donuts need a stronger flour due to the abuse of pressure extrusion. Spring wheat flours are normally used.
Spring wheats are planted in the spring in the northern states and harvested in the fall. Spring wheats are much higher in protein than the winter wheats are used to produce high gluten flours. Average high gluten flours range in protein from 12.5% protein to 14% protein. The proteins in spring wheat flour are much stronger than winter wheat proteins.
Winter wheat are planted in the winter in the central and southern states and are harvested in the late spring. Winter wheats are used to produce bread flours. Average hard red winter wheat flours contain 10.0 to 11.0% protein.
The most important specification is the protein level. Lowering the protein level to save money will result in collapsing donuts with high-fat levels. Using too high a protein will result in tough donuts with low-fat levels.
The next most important specification is ash. Ash level indicates the degree of extraction or how many pounds of flour was produced from the wheat. The higher the extraction, the higher the ash, the higher the protein, and the lower the protein quality. DO NOT ACCEPT HIGH ASH LEVEL FLOURS. These flours are no good for producing quality donuts. Winter wheat ash levels should be below .49 and spring wheat ash levels should be below .53.
There are many other parameters that measure protein quality such as the farinograph which accurately predict protein quality.
High gluten flour can produce a much richer product than winter wheat due to the dilution of the proteins. The richer the product, the stronger the flour should be. Other factors are the abuse the flour receives during mixing and processing. Very high-speed mixers and abusive pumping will require a stronger flour. Gentle mixing and no pumping do not require a stronger flour
Which Flour to Use
Picking the correct flour is vital to producing quality donuts. Flour can effect many different aspects of the finished product such as volume, toughness, fat absorption, and shelf life. All of the parameters of the finished product must be taken into consideration when selecting the flour. Contact Bakery Science if you have questions on which flour to pick.
Sugar has several functions in a yeast raised dough. The obvious is sweetness, however, this is the least important. In a yeast donut, there is Dextrose, Sucrose, and other sugars.
Sugar acts as a tenderizer which will make the donut less chewy and will increase the fat absorption. Sugar will also undergo browning reactions during frying to give crust color, dextrose gives more crust color than sucrose.
The most important function is a food for the yeast. The yeast needs a supply of quick energy for the quick fermentation that is used. Dextrose will be the primary source of food for the yeast during the fermentation.
Low levels of sugars speed up fermentation considerably, but as the sugar levels rise, sugar will inhibit fermentation due to the osmotic pressure exerted on the yeast.
Sugar will also compete with the gluten for the available water. To see this, mix a dough with no sugar and very low water. The dough will be very stiff. Add sugar at the end of the mixing and the dough will soften up considerably. This is why high sugar doughs are so low in sugar. This magnifies the osmotic pressure and slows the fermentation down even more. Doughs with very high sugar levels need very high levels of yeast to compensate for the slow fermentation
Donut Dough Shortening
There are many types of shortenings on the market. The best shortening to use is a yeast raised Emulsified vegetable shortening.
A yeast-raised shortening is a solid shortening with low IV monoglycerides added. Avoid using icing shortenings.
Monoglycerides is a very general term. Only two monoglycerides are functional in yeast raised dough and that one is glycerol monostearate (GMS) and glycerol mono palmitate (GMP). GMS and GMP are the only monoglycerides that function as a crumb softener. GMS and GMP content of a good yeast raised shortening will be 5 to 10%. Powdered monoglycerides are a blend of GMS/GMP and GMO (glycerol monooleate). The GMO is used to make the GMS soluble in water. Straight GMS must be melted into fat in order for it to be functional. GMO is not functional in yeast raised products even though it is a monoglyceride. In other words, you are paying top dollar for a nonfunctional ingredient!
Yeast is a living ingredient. Care must be taken with yeast so that it is not stressed or killed.
Compressed yeast or cream yeast is the best yeast to use in donuts. This yeast has been stressed the least. Compressed yeast is in a semi-dormant state that will allow the yeast to have a shelf life of about 7 days. Do not use old yeast. Do not use hot yeast that has broken down. Yeast should feel cold and dry, not sticky. Many yeast companies are putting codes of 2 weeks on yeast. Do not keep your yeast that long. Get more frequent deliveries.
Compressed yeast must be kept cold and not allowed to warm up. Once compressed yeast is warmed up the yeast starts fermenting itself (eating itself) and the temperature increases more. This process is very hard to stop and will destroy the yeast. Once the yeast cell has been ruptured due to this process the enzymes that were contained in the yeast are released into the dough. These enzymes will destroy the dough. Yeast must be kept in a sealed bag, this will also keep the yeast in a dormant stage.
Dry yeast takes much too long to come out of dormancy. The dry process stresses the yeast far too much and the short fermentation of yeast donuts does not give the yeast a chance to "come back". Dry yeast requires much longer fermentation times.
Pure granulated sugar and salt are poisonous to yeast. Never scale the yeast directly on top of sugar or salt. Keep the two separated until mixing.