Baker's yeast

Source: Wikipedia, the free encyclopedia.
Saccharomyces cerevisiae, the yeast commonly used as baker's yeast. Gradation marks are 1 µm apart.

Baker's yeast is the common name for the strains of

brewer's yeast or the deactivated form nutritional yeast.[2]
Baker's yeast is also a single-cell microorganism found on and around the human body.

The use of steamed or boiled

eggs, slow down yeast growth;[7] others say the effect of fat on dough remains unclear, presenting evidence that small amounts of fat are beneficial for baked bread volume.[8]

sourdough starter
.

History

A block of compressed fresh yeast in its wrapper

It is not known when yeast was first used to bake bread; the earliest definite records come from Ancient Egypt.[9] Researchers speculate that a mixture of flour meal and water was left longer than usual on a warm day and the yeasts that occur in natural contaminants of the flour caused it to ferment before baking. The resulting bread would have been lighter and tastier than the previous hard flatbreads. It is generally assumed that the earliest forms of leavening were likely very similar to modern sourdough; the leavening action of yeast would have been discovered from its action on flatbread doughs and would have been either cultivated separately or transferred from batch to batch by means of previously mixed ("old") dough. Also, the development of leavened bread seems to have developed in close proximity to the development of beer brewing, and barm from the beer fermentation process can also be used in bread making.

Without an understanding of

wort, usually including malted barley and wheat flour. Such cultures (sometimes referred to in old American cookery as "emptins", from their origins as the dregs of beer or cider fermentation) became the ancestors of modern baker's yeast, as, in general, they were carefully maintained to avoid what was later discovered to be bacterial contamination, including using preservatives such as hops
as well as boiling the growth medium.

In the 19th century, bread bakers obtained their yeast from beer brewers, and this led to sweet-fermented breads such as the Imperial "Kaiser-Semmel" roll,[10] which in general lacked the sourness created by the acidification typical of Lactobacillus. However, beer brewers slowly switched from top-fermenting to bottom-fermenting yeast (Saccharomyces pastorianus) and this created a shortage of yeast for making bread, so the Vienna Process was developed in 1846.[11] While the innovation is often popularly credited for using steam in baking ovens, leading to a different crust characteristic, it is notable for including procedures for high milling of grains (see Vienna grits[12]), cracking them incrementally instead of mashing them with one pass; as well as better processes for growing and harvesting top-fermenting yeasts, known as press-yeast.

Refinements in microbiology following the work of Louis Pasteur led to more advanced methods of culturing pure strains. In 1879, Great Britain introduced specialized growing vats for the production of S. cerevisiae, and in the United States around the turn of the century centrifuges were used for concentrating the yeast,[13] making modern commercial yeast possible, and turning yeast production into a major industrial endeavor. The slurry yeast made by small bakers and grocery shops became cream yeast, a suspension of live yeast cells in growth medium, and then compressed yeast, the fresh cake yeast that became the standard leaven for bread bakers in much of the Westernized world during the early 20th century.

During World War II, Fleischmann's developed a granulated active dry yeast for the United States armed forces, which did not require refrigeration and had a longer shelf-life and better temperature tolerance than fresh yeast; it is still the standard yeast for US military recipes. The company created yeast that would rise twice as fast, cutting down on baking time.

In 1973, Lesaffre created instant yeast (also called "quick rise" or "fast acting" yeast), which has gained considerable use and market share at the expense of both fresh and active dry yeast in their various applications. Instant yeast differs from active dry yeast in several ways: Instant yeast rises faster than active dry yeast; instant yeast can be directly added to the dry ingredients, whereas active dry yeast should be mixed with liquid (water, milk or beer) and proofed before mixing; instant yeast has a lower moisture content; and instant yeast is formed of smaller granules.

Modern baker's yeast is the species

sorbates do inhibit yeast fermentation activity, so are not added directly to yeast-leavened doughed but may be sprayed onto finished products or even incorporated into packing materials.[15]

Types of baker's yeast

Yeast, baker's, active dry
Nutritional value per 100 g (3.5 oz)
Energy1,361 kJ (325 kcal)
41.22 g
Sugars0 g
Dietary fiber26.9 g
7.61 g
40.44 g
Niacin (B3)
251%
40.2 mg
Pantothenic acid (B5)
270%
13.5 mg
Vitamin B6
88%
1.5 mg
Folate (B9)
585%
2340 μg
Choline
6%
32 mg
Vitamin C
0%
0.3 mg
MineralsQuantity
%DV†
Calcium
2%
30 mg
Iron
12%
2.17 mg
Magnesium
13%
54 mg
Manganese
14%
0.312 mg
Phosphorus
51%
637 mg
Potassium
32%
955 mg
Sodium
2%
51 mg
Zinc
72%
7.94 mg
Other constituentsQuantity
Water5.08 g
Link to USDA Database entry
†Percentages estimated using US recommendations for adults,[16] except for potassium, which is estimated based on expert recommendation from the National Academies.[17]
Active dried yeast, a granulated form in which yeast is commercially sold

Baker's yeast is available in a number of different forms, the main differences being the moisture contents.[18] Though each version has certain advantages over the others, the choice of which form to use is largely a question of the requirements of the recipe at hand and the training of the cook preparing it. Dry yeast forms are good choices for longer-term storage, often lasting more than a year at room temperatures without significant loss of viability.[19] In general, with occasional allowances for liquid content and temperature, the different forms of commercial yeast are considered interchangeable.

  • Cream yeast is the closest form to the yeast slurries of the 19th century, in essence being a suspension of yeast cells in liquid, siphoned off from the growth medium. Its primary use is in industrial bakeries with special high-volume dispensing and mixing equipment, and it is not readily available to small bakeries or home cooks.[20]
  • Compressed yeast is, in essence, cream yeast with most of the liquid removed. It is a soft solid, beige in color, and best known in the consumer form as small, foil-wrapped cubes of cake yeast. It is also available in a larger-block form for bulk usage.[21] It is highly perishable; though formerly widely available for the consumer market, it has become less common in supermarkets in some countries due to its poor keeping properties, having been superseded in some such markets by active dry and instant yeast. It is still widely available for commercial use, and is somewhat more tolerant of low temperatures than other forms of commercial yeast; however, even there, instant yeast has made significant market inroads.
  • Active dry yeast is the form of yeast most commonly available to non-commercial bakers in the United States. It consists of coarse oblong granules of yeast, with live yeast cells encapsulated in a thick jacket of dry, dead cells with some growth medium. Under most conditions, active dry yeast must first be proofed or rehydrated. It can be stored at room temperature for a year, or frozen for more than a decade, which means that it has better keeping qualities than other forms, but it is generally considered more sensitive than other forms to thermal shock when actually used in recipes.
A single grain of active dry yeast. The numbered ticks on the scale are 230 µm apart.

Difference between instant and active dry yeast

Instant and active dry yeast are essentially the same ingredient, just in slightly different forms and applications. Consumers should keep sealed packets of both yeast types at room temperature and store partially used packets in an airtight container in the refrigerator. The main differences between the two are:

  • Active yeast needs rehydration. Instant yeast can be mixed directly into dry ingredients, whereas active dry yeast must first be dissolved and rehydrated in warm water.
  • Instant yeast needs less time to rise. Since instant yeast has a finer texture than active dry yeast, it is possible to skip the initial rise time and shape loaves immediately after kneading. Loaves made with active dry yeast require longer rising times for the yeast to work its way through the dough.[25]

Commercial brands

For most commercial uses, yeast of any form is packaged in bulk (blocks or freezer bags for fresh yeast; vacuum-packed brick bags for dry or instant); however, yeast for home use is often packaged in pre-measured doses, either small squares for compressed yeast or sealed packets for dry or instant. For active dry and instant yeast, in general a single dose (reckoned for the average bread recipe of between 500 g and 1000 g of dough) is about 2.5 tsp (~12 mL) or about 7 g (1⁄4 oz), though comparatively lesser amounts are used when the yeast is used in a pre-ferment. In general, a yeast flavor in the baked bread is not noticeable when the bakers' percent of added yeast is less than 2.5%.[26]

Notable commercial brands of baker's yeast include Lesaffre's SAF red and SAF gold, Fleischmann's, and Red Star Yeast.[citation needed]

Use in research

Model organism

Because it is readily available and easy to culture, baker's yeast has long been used in chemical, biological, and genetic research as a

cell division cycle was worked out from experiments with yeast.[27]

Organic synthesis

Reduction of a carbonyl to a hydroxyl with baker's yeast

Baker's yeast contains

organometallic carbonyl compounds in very high yield.[29]

Psychoactive drugs

Industrial production

The baking industry relies on industrial production of its ingredients, including baking yeasts. Much effort has been put into developing and marketing yeasts that will perform reliably in mass production. Since the end of the nineteenth century, baker's yeast has been produced by companies that specialize in its production.[citation needed]

The main ingredients for industrial production are yeast cultures, sugar from cane and sugar beet; but a number of minerals, nitrogen and vitamins are also needed.[31]

Fermentation happens in several phases, which vary depending on the manufacturer:[31][32]

  • pure cultures in a laboratory flask for 2 to 4 days, then batch fermentations for 13 to 24 hours (anaerobic);
  • intermediate and stock fermentation with gradual feeding and constant aeration;
  • pitch and trade fermentation with large air supplies for up to 15 hours;
  • filtration, blending, extrusion, and cutting, drying.

The yeast grows from hundreds kg in the intermediate and stock fermentor to tens of thousands kg in the trade fermentor, where most yeast is produced.[31] The earlier stages produce more ethanol and other alcohols, while in the final stages ethanol production is suppressed up to 95% by controlling the amount of oxygen and sugar, in order to increase the yeast production instead.[31]

The industry is highly concentrated, with five companies holding up to 80% of the worldwide market for dry yeast as of 2006. While dry yeast is exported over long distances and mostly sold in the developing countries, industrial customers often prefer to supply fresh yeast from local facilities, with a single wholesaler having up to 90% of the liquid yeast market in the UK in 2006.[33] In the US companies like Lesaffre Group, AB Vista, GB Plange and AB Mauri produced hundreds of thousands of metric tons of yeast in 2012.[citation needed]

See also

Wikimedia Commons has media related to Baker's yeast.

Further reading

  • Corriher, Shirley, Cookwise. New York: William Morrow and Co., 1997,
    ISBN 0-688-10229-8
    .
  • Editors of Cook's Illustrated Magazine, Baking Illustrated. Brookline, MA:Boston Common Press, 2004,
    ISBN 0-936184-75-2
    .
  • The King Arthur Flour Baker's Companion. Woodstock, Vermont: Countryman Press, 2003,
    ISBN 0-88150-581-1
    .
  • Simmons, Amelia. American Cookery, Hartford, 1798. Text at Feeding America and Project Gutenberg.
  • Sloat, Caroline (ed.), Old Sturbridge Village Cookbook 2ed.. Old Saybrook: Globe Pequot Press, 1995,
    ISBN 1564407284
    .
  • OMRI for the USDA National Organic Program (2014-01-22). Yeast Handling/Processing, Technical Evaluation Report (PDF).

References

  1. ISBN 978-0-387-38563-1. Archived
    from the original on 2016-05-12. Retrieved 2015-10-27. The scientific name for baker's yeast is Saccharomyces cerevisiae, ...
  2. ^ Kalmus, Sage. "What Is the Difference Between Brewer's Yeast & Baker's Yeast?". livestrong.com. Archived from the original on 21 May 2013. Retrieved 14 May 2013.
  3. ^ Eben Norton Horsford (1875). Report on Vienna bread - Internet Archive. Washington: Government Printing Office. pp. 90, 88, 87. potatoes.
  4. ^ Samuel P. Sadtler (1908). A hand-book of industrial organic ... - Google Books. J. B. Lippincott Company. p. 235. Archived from the original on 2022-01-12. Retrieved 2020-10-15.
  5. ISBN 978-0-306-47363-0
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  6. ISBN 978-0-387-38563-1
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  7. ISBN 978-1-58816-398-1
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  8. ISBN 978-0-387-38563-1. Archived
    from the original on 2013-10-09. Retrieved 2011-04-25.
  9. ^ "The History of Bread Yeast" Archived 2011-10-01 at the Wayback Machine. BBC. Retrieved December 24, 2006.
  10. ^ Eben Norton Horsford (1875). Report on Vienna bread - Internet Archive. Washington: Government Printing Office. p. 86. sweet.
  11. ISBN 978-0-521-77917-3
    .
  12. ^ Eben Norton Horsford (1875). Report on Vienna bread - Internet Archive. Washington: Government Printing Office. pp. 31–32. sweet.
  13. ISBN 978-0-521-32749-7
    .
  14. ISBN 9781439800454. Archived
    from the original on 2022-01-12. Retrieved 2020-06-13.
  15. ^ "Clean Label Mold Inhibitors for Baking". July 2016. Archived from the original on 2020-06-14. Retrieved 2020-06-14.
  16. ^ United States Food and Drug Administration (2024). "Daily Value on the Nutrition and Supplement Facts Labels". Retrieved 2024-03-28.
  17. PMID 30844154.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  18. ISBN 978-0-387-38563-1
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  19. PMID 13725540
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  20. ^
    ISBN 978-1-58008-268-6
    .
  21. ISBN 978-0-471-78349-7
    .
  22. ISBN 978-0-8247-8276-4. Archived
    from the original on 2013-10-09. Retrieved 2011-04-24.
  23. ISBN 978-0-07-048703-1
    .
  24. ^ "San Francisco Baking Institute Newsletter" (PDF). 2003. Archived from the original (PDF) on 2015-09-24. Retrieved 2015-01-12.
  25. ^ "Instant Yeast vs. Active Dry Yeast: What Is The Difference?". MasterClass. Archived from the original on 2022-01-10. Retrieved 2022-01-10.
  26. ISBN 978-1-85573-553-8. Archived
    from the original on 2022-01-12. Retrieved 2020-10-15.
  27. ^ "Cytokinesis in Yeast | Learn Science at Scitable". www.nature.com. Retrieved 2022-10-13.
  28. ISSN 0009-2665
    .
  29. ISBN 9780470856253. Archived
    from the original on 2022-01-12. Retrieved 2015-10-27.
  30. PMID 35132076
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  31. ^ a b c d EFIG (1996). 9.13.4 Yeast Production (PDF). EPA. Archived (PDF) from the original on 2017-04-28. Retrieved 2017-08-19.
  32. ^ "Lallemand production process" (PDF). 2011. Archived (PDF) from the original on 2020-04-05. Retrieved 2017-08-19.
  33. ^ European Commission (2008-07-11). Case No COMP/M.5020 - LESAFFRE / GBI UK (PDF). Archived (PDF) from the original on 2017-08-19. Retrieved 2017-08-19.
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