Yeast - Ultra Low Brewing

Yeast Strains with Potential for the Production
of Non-Alcoholic and Ultralow Alcohol Beers.

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When it comes to the fermentation of wort, selecting the right yeast is just as important as selecting the recipe style. Choosing the wrong strain could skew the beer into a different category, resulting in a less than ideal result, a few key factors in selecting the right yeasts are; ester production, attenuation, temperature ranges, top or bottom fermenting (ale or lager), POF+, STA1+, failing to choose a suitable strain may result in undesirable sensory profiles and characteristics, and/or over/under-attenuation.

When brewing NAB/LAB, selecting the right strain is even more crucial, as over attenuation may result in higher ABV%, and a neutral profile may not create the right flavour characteristics, leaving the brewer with a plain, thin beer.

You can find on this page a list of proven, and untested yeast strains that may have potential in creating great results. The information provided has been best detailed, based on available information from manufacturers, listing where available; genus, attenuation, suited styles, and sensory characteristics.
The untested use of some of these strains may result in undesirable results, causing loss within a brewers brewhouse, consideration must be taken whether a particular strain is suitable the brewer.

Beer Strains & Information

With the increase in non-Saccharomyces species/novel strains making their way into the production of non-alcoholic/ultra-low alcohol beer, the use of these varieties holds great potential for the NAB/LAB sector in the fermentation of wort. With a trial and selection process, yeast manufactures have been able to isolate specific strains of these novel strains to assist in low fermentability in NAB/LAB production.

In this catalogue, you will find multiple strains available from different manufactures that may aid brewers in creating lower alcohol beers, whilst these strains have not all been tested in NAB/LAB production, results may vary, creating un-desirable characteristics such as phenolic of flavours (POF) and risk cross-contamination. Where applicable, these strains “may” contribute positive flavour/aroma profiles. Brewers are to use the information provided as a “guide” only, as some of the information may be unavailable from manufactures, or incorrect at the time of publishing, and should be used on smaller test batches, as to not spoil large quantities of beer, resulting in costly losses. If the brewer is unsure if the use of these yeasts are suitable to their brewery, it is advised not to use them, and proceed with “standard” strains to avoid waste or loss.

Information regarding compatibility on these strains may be updated in time, by myself, or other brewers test these strains against wort fermentation and compatibility and contribute to this paper to assist in clarification on flavour/aroma profiles, fermentability, off flavours, and the overall outcome of the beer.

Regular brewer’s yeast strains that are currently available to the public market are perfectly fine to brew ultra-low and non-alcoholic beers with. In fact, I quite often use strains such a Lallemand’s “Verdant IPA”, or Mangrove Jacks “M54” Californian Lager strain in my regular rotation. When I select a strain that assimilates most of the sugars in the wort, I ensure to structure my recipe based around the attenuation I typically observe in my brewing notes. This enables me to finish with a low abv that I desire when designing the beer, while using a standard strain.

A great option that we regularly endorse, is the use of a maltotriose negative strain. These strains can easily ferment out the simple sugars (glucose, fructose, sucrose), and the maltose sugars, yet they have either, limited ability or completely inhibited ability to consume the larger sugars such as maltotriose, dextrins and other complex and unfermentable sugars.

In the table below, you can find a list of common yeast strains from various manufacturers that have the maltotriose negative gene, or are very low attenuating yeast that are comparable to create an ultra-low or non-alcoholic beer with ease.

Yeast	Factor	Result	Esters/Flavours
Fermentis SafAle™ S33 Saccharomyces Cerevisiae	Consumes Maltose	Yes	Fruity driven strain gives a high mouthfeel and body to the beer. Yeast with a medium sedimentation forms no clumps but a powdery haze when resuspended in the beer. Uses: Blonde/Pales, Amber, Stout, American and British Ales, Hazy IPA’s, NEIPA’s.
	Consumes Maltotriose	No
	Attenuation	68-72%


Fermentis SafAle™ F-2 Cask & Bottle Conditioning Yeast Saccharomyces Cerevisiae	Consumes Maltose	Yes	Neutral Flavour & Aroma. Uses: Well suited for primary fermentation of sweeter Fruit Beers or full-bodied, Malty Ales. Also, Dry Ciders, Mead, Hard Seltzer.
	Consumes Maltotriose	No
	Attenuation	High (Simple Sugars) Low-Med (Beer Wort)


Lallemand Windsor™ Saccharomyces Cerevisiae	Consumes Maltose	Yes	Produces a balanced fruity aroma and imparts a slight fresh yeasty flavour. Beers created with Windsor are usually described as full-bodied, fruity English ales, sweet. Uses: Milds, Bitters, English Brown Ales, Porters, Stouts, Pale Ale, IPA, New England IPA, Ambers, American Ales.
	Consumes Maltotriose	No
	Attenuation	Medium


Lallemand CBC-1™ Cask & Bottle Conditioning Yeast Saccharomyces Cerevisiae	Consumes Maltose	Yes	Neutral Flavour & Aroma. Uses: Well suited for primary fermentation of sweeter Fruit Beers or full-bodied, Malty Ales. Also, Dry Ciders, Mead, Hard Seltzer.
	Consumes Maltotriose	No
	Attenuation	High (Simple Sugars) Low-Med (Beer Wort)


Whitelabs WLP002 English Ale Yeast Saccharomyces Cerevisiae	Consumes Maltose	Yes	Residual sweetness accentuates malt character along with mild fruity esters, adding complexity to the flavour and aroma of finished beers. Slight diacetyl production is common. Due to this strain’s high flocculation, the beer will finish clear. The low attenuation points towards being maltotriose negative. Uses: Pale Ale, IPA, Brown Ale, English Bitter.
	Consumes Maltotriose	Unavailable
	Attenuation	63-70%


Whitelabs WLP011 European Ale Yeast Saccharomyces Cerevisiae	Consumes Maltose	Yes	Low ester production gives it a clean profile, with little to no sulphur production. Low attenuation helps to contribute to the malty character. Uses: Altbiers, Kolsch-style Ales, Malty English-style Ales, and Fruit Beers.
	Consumes Maltotriose	Unavailable
	Attenuation	65-70%


Whitelabs WLP036 Dusseldorf Alt Ale Yeast Saccharomyces Cerevisiae	Consumes Maltose	Yes	It produces clean, malty German brown and amber ales. This strain keeps the contribution of hop bitterness in the background while promoting sweet malt notes. Uses: Altbier, Cream Ale, Kolsch, Red Ale.
	Consumes Maltotriose	Unavailabe
	Attenuation	65-72%


Whitelabs WLP546 Marañón Canyon Wild Cacao Yeast Saccharomyces Cerevisiae	Consumes Maltose	Yes	The fruity, phenolic, and wild-like characteristics of this strain make it an ideal choice for farmhouse and Saison-style beers. Uses: Saison, Wild Specialty Beer.
	Consumes Maltotriose	Unavailable
	Attenuation	65-70%


Whitelabs WLP611 New Nordic Ale Yeast Saccharomyces Cerevisiae x Torulaspora Delbrueckii	Consumes Maltose	Yes	This culture is a unique blend of three yeast strains (two belonging to Saccharomyces cerevisiae and one Torulaspora delbrueckii. Used to make a series of true New Nordic Beers. This blend has a specific aroma profile, especially at higher temperatures Uses: Belgian Saison, Belgian Pale Ale, Weizenbock, Weissbier, German Hefeweizen.
	Consumes Maltotriose	Unavailable
	Attenuation	65-75%


Whitelabs WLP820 Oktoberfest/Märzen Lager Yeast Saccharomyces Pastorianus	Consumes Maltose	Yes	This strain is ideal for producing malty lagers. Residual sweetness further helps promote malt nuances while contributing to a balanced finish. Uses: Lagers, Pilsners, Helles, Märzen.
	Consumes Maltotriose	Unavailable
	Attenuation	65-73%


Wyeast 1099 Whitbread Ale™ Saccharomyces Cerevisiae	Consumes Maltose	Yes	A mildly malty and slightly fruity fermentation profile. Good flocculation characteristics, this yeast clears well without filtration. Low fermentation temperatures will produce a clean finish with a very low ester profile. Uses: British Ales, Stout, IPA, Blonde Ale, Bitters.
	Consumes Maltotriose	Unavailable
	Attenuation	68-72%


Wyeast 1187 Ringwood Ale™ Saccharomyces Cerevisiae	Consumes Maltose	Yes	Distinct fruit esters with a malty, complex profile. Flocculation is high, and the beer will clear well without filtration. A thorough diacetyl rest is recommended after fermentation is complete. This strain can be a slow starter and fermenter. Uses: Porter, Brown Ales, Dark Milds, Stouts, IPAs.
	Consumes Maltotriose	Unavailable
	Attenuation	68-72%


Wyeast 1332 Northwest Ale™ Saccharomyces Cerevisiae	Consumes Maltose	Yes	Produces a malty and mildly fruity ale with good depth and complexity. Uses: Pale Ales, IPA, Amber Ale, Stout, Blonde Ale.
	Consumes Maltotriose	Unavailable
	Attenuation	67-71%


Wyeast 1496 West Yorkshire Ale™ Saccharomyces Cerevisiae	Consumes Maltose	Yes	Produces ales with a full chewy malt flavour and character, but finishes dry, producing balanced beers. Moderate nutty and stone-fruit esters. Uses: Bitters, ESB, Mild Ales.
	Consumes Maltotriose	Unavailable
	Attenuation	67-71%


Wyeast 1728 Scottish Ale™ Saccharomyces Cerevisiae	Consumes Maltose	Yes	Suited for the strong, malty ales of Scotland. This strain is very versatile and is often used as a “House” strain as it ferments neutral and clean. Higher fermentation temperatures will result in an increased ester profile. Uses: Scottish Ales, Stout, IIPA, Specialty Ale.
	Consumes Maltotriose	Unavailable
	Attenuation	69-73%


Wyeast 1768-PC English Special Bitter™ Saccharomyces Cerevisiae	Consumes Maltose	Yes	Produces light fruit and ethanol aromas along with soft, nutty flavours. Exhibits a mild malt profile with a neutral finish. Uses: Bitters, Stout, IPA.
	Consumes Maltotriose	Unavailable
	Attenuation	68-72%


Wyeast 1968-PC London ESB Ale™ Saccharomyces Cerevisiae	Consumes Maltose	Yes	Extremely flocculent yeast produces distinctly malty beers. Ales produced with this strain tend to be fruity, increasingly so with higher fermentation temperatures. A thorough diacetyl rest is recommended after fermentation is complete. Uses: Bitters, Ales, Fruit Beers, English IPA
	Consumes Maltotriose	Unavailable
	Attenuation	67-71%


WHC Lab Low Rider-Session Saccharomyces Cerevisiae	Consumes Maltose	Yes	Produces a moderate amount of biotransformation and glycerol production. Accentuate tropical and citrus hop aromas, bringing a burst of juicy pineapple, mango, and citrus notes to the forefront of the beer. Uses: Pale Ale, IPA, NEIPA, Stout.
	Consumes Maltotriose	No
	Attenuation	63-68%


Escarpment Labs Elysium Saccharomyces Cerevisiae	Consumes Maltose	Yes	Balanced hop biotransformation profile (thiols and terpenes). Can be fermented warm or with a free rise, enhancing pineapple ester production. Also suited to fermenting sours. Uses: IPA, Pale Ale, NEIPA, Sours.
	Consumes Maltotriose	Unknown
	Attenuation	68-76%


Escarpment Labs Goldrush Lager Saccharomyces Pastorianus	Consumes Maltose	Yes	This strain is able to ferment at warmer temperatures than many lager strains, yet it still produces characteristic lager flavours. Slightly fruity, malt-forward, clean. Uses: Lager, Californian Common.
	Consumes Maltotriose	Unknown
	Attenuation	63-72%


Escarpment Labs Hydra Saccharomyces Cerevisiae	Consumes Maltose	Yes	Hydra strain provides big juicy flavour coupled with strong mango and citrus aromatics, along with stone fruit. Uses: IPA American Pale Ale, Pale Ale, NEIPA.
	Consumes Maltotriose	Unknown
	Attenuation	65-72%


Escarpment Labs Thiol Libre Saccharomyces Cerevisiae	Consumes Maltose	Yes	Unlock bolder tropical fruit aromas in your brews with Thiol Libre. Beers fermented with Thiol Libre have enhanced guava, passionfruit, and grapefruit aromas. Uses: IPA American IPA, Pale Ale, NEIPA.
	Consumes Maltotriose	Unknown
	Attenuation	68-80%


Omega Yeast OYL‑003 London Ale Saccharomyces Cerevisiae	Consumes Maltose	Yes	The London Ale strain has obvious English character in its pronounced minerality and mild fruit notes. It performs best for dry, crisp beers, and in highlighting hop bitterness. Uses: Pale Ale, IPA, Bitters
	Consumes Maltotriose	Unavailable
	Attenuation	67-77%


Omega Yeast OYL‑007 British Ale II Saccharomyces Cerevisiae	Consumes Maltose	Yes	Flexible, leaves near spotless clarity, and has more fruit-like esters and malt than British Ale I. Select for malt and fruit at higher fermentation temperatures or a clean profile at lower temperatures. Uses: Pale Ale, IPA, Milds, Bitters
	Consumes Maltotriose	Unavailable
	Attenuation	68-72%


Omega Yeast OYL‑012 Pacific NW Ale Saccharomyces Cerevisiae	Consumes Maltose	Yes	Presents a relatively neutral profile with notes of malt and light fruit that add depth of flavour. It is a healthy flocculator. Uses: Pale Ale, IPA, Bitters
	Consumes Maltotriose	Unavailable
	Attenuation	67-71%


Omega Yeast OYL‑014 British Ale VII Saccharomyces Cerevisiae	Consumes Maltose	Yes	This strain produces very clean, well balanced ales that are both significantly malty and have esters reminiscent of stone fruit with dry, nutty tones at the back end. Uses: Pale Ale, Cask Ale, Milds, Bitters
	Consumes Maltotriose	Unavailable
	Attenuation	67-71%


Omega Yeast OYL‑016 Extra Special Saccharomyces Cerevisiae	Consumes Maltose	Yes	A ridiculously thorough flocculator thought to be from a highly regarded English ESB. This strain has unique fruitiness and noticeable finishing sweetness, but needs a diacetyl rest. To enhance the fruit, ferment up at the recommended temperature ceiling. Uses: Pale Ale, NEIPA, Milds, Bitters
	Consumes Maltotriose	Unavailable
	Attenuation	67-71%


Omega Yeast OYL‑432 Extra Special+ Saccharomyces Cerevisiae	Consumes Maltose	Yes	A popular choice to create an expressive base for IPAs and classic English styles, without the need for a diacetyl rest due to the expression of the ALDC enzyme. Drops remarkably clear, leaving behind only nuanced esters with a dash of residual sweetness. Uses: Pale Ale, IPA, Milds, Bitters
	Consumes Maltotriose	Unavailable
	Attenuation	67-71%


Imperial Yeast I22 Capri Saccharomyces Cerevisiae	Consumes Maltose	Yes	The Juicy ester aromatics of A38 Juice fuse with the tropical flavours and bright citrus notes of A43 Loki. This strain works especially well with dry-hop additions just before the end of active fermentation. Uses: American IPA, IPA, Pale Ale, NEIPA
	Consumes Maltotriose	Unavailable
	Attenuation	68-74%

As the table shows, there are an array of maltotriose negative yeast strains available to homebrewers. To take it one step further, manufacturers are increasing their focus and resources into developing and isolating maltose negative strains. Unfortunately, not all of these strains are readily available to the homebrew market. Most are reserved for “professional use only” due to the requirements needed to ensure a stable packaged product through the means of pasteurisation, which is something that cannot be policed throughout the domestic market.

We’ve had the privilege to use of some of these amazing new strains, and they’ve made some really fantastic beer. It’s easy to see why so many commercial breweries are adopting these strains into their brewhouses to make some of the incredible beers they’ve been producing.

In the table below is a list of some commonly know strains that have come to fruition from various manufacturers.

Yeast	Factor	Result	Esters/Flavours
Fermentis SafBrew™ LA-01 Saccharomyces Cerevisiae var. chevalieri	Consumes Maltose	No	This yeast does not assimilate maltose and maltotriose but assimilates simple sugars (glucose, fructose, and sucrose) and is characterized by a subtle aroma profile. POF+, not suitable for use with wheat. Pasteurization is required. Uses: Suits most beer styles
	Consumes Maltotriose	No
	Attenuation	13-17%


Lallemand LoNa™ Saccharomyces Cerevisiae	Consumes Maltose	No	Performs like an ale yeast producing a clean and neutral aroma profile with no phenolic off-flavours, and significantly reducing aldehydes that cause worty flavours. Does not consume maltose or maltotriose, resulting in very low attenuation. Pasteurization is required. Uses: Suits all beer styles
	Consumes Maltotriose	No
	Attenuation	16-20%


Escarpment Labs NAY Hanseniaspora uvarum	Consumes Maltose	No	Whether you want a clean, refreshing lager or a fruitier, hoppier IPA, NAY will help you achieve the perfect results. With excellent flavour and performance in beers below 0.5% ABV. Pasteurization is required. Uses: Suits all beer styles
	Consumes Maltotriose	No
	Attenuation	10-20%


Whitelabs WLP603 Torulaspora delbrueckii Vault Strain	Consumes Maltose	No	The profile of this strain has high ester production and will lend well to styles such as a fruit-forward IPA or Saison. This species does not ferment maltose or other larger sugars and will only ferment glucose, sucrose, and fructose. Pasteurization is required. Uses: IPA, Pale Ale, Saison, Kolsch
	Consumes Maltotriose	No
	Attenuation	~20%


Whitelabs WLP618 NA All Day Saccharomycodes Ludwigii	Consumes Maltose	No	This specific strain has been chosen because of its lower ethyl acetate production compared to similar strains. This species is maltose negative as it does not ferment maltose or other larger sugars and will only ferment the glucose, sucrose, and fructose. Pasteurization is required. Uses: IPA, Pale Ale, Kolsch, Lager, Pilsner
	Consumes Maltotriose	No
	Attenuation	~20%


Whitelabs WLP686 Zygosaccharomyces Lentus Vault Strain	Consumes Maltose	No	Maltose negative strain. The profile of this strain is found to be very neutral. This species is slower and might take longer to reduce sugars and lower the pH of the beer compared to other strains. Little ester production was perceived in lab scale trials. Pasteurization is required. Uses: IPA, Pale Ale, Kolsch, Lager, Pilsner
	Consumes Maltotriose	No
	Attenuation	~20%


Whitelabs WLP4650 Metschnikowia Reukaufii	Consumes Maltose	No	Metschnikowia reukaufii is a nectar specialist that was isolated from flowers. This maltose negative yeast evolved to produce a more odorous and attractive nectar for pollinators by enzymatically altering otherwise inodorous nectar compounds including glycosides. Pasteurization is required. Uses: IPA, Pale Ale, Hazy, Kolsch, Lager, Pilsner
	Consumes Maltotriose	No
	Attenuation	20-25%

You can utilise any strain of yeast for fermentation, but it is better practice to choose a suitable strain, that is either Maltose and/or maltotriose negative to reduce the attenuation of the sugars available in the wort. Avoid choosing a strain that tests positive for the “STA1” gene, the presence of the “STA1” gene causes the yeast to secrete glucoamylase, an enzyme which hydrolyses dextrins and starches into fermentable sugars. The yeast is now a “hyper attenuator” as it ferments beer beyond what ordinary brewer’s yeast is capable.

Beer contaminated with even a small amount of S.diastaticus will first ferment normally with the expected level of attenuation. After packaging, the secreted glucoamylase will continue to break down these complex carbohydrates into glucose over the subsequent months. The glucose will then be fermented by all yeasts present, producing alcohol and CO2. Since the beer is already packaged, the generated CO2 causes over-pressurization, leading both to gushing and the more dangerous effects of package failure.

Dry or Full-Bodied Beers?

Find the right balance between residual sugars and final alcohol with Fermentis ©.(Source 10.31)

Almost all of our yeast strains guarantee a medium/high attenuation rate: around 78-84%. If you want to obtain a beer with a higher attenuation and a low level of residual sugars, SafAle™ BE-256 or SafAle™ BE-134 will be the obvious choices. Likewise for high-density beers, SafAle™ HA-18 will allow a very high attenuation. However, if you want to obtain a medium level of residual sugars, SafAle™ S-33 will fit perfectly.

Residual sugars:
Looking for yeast which leave some specific sugars behind?

(Table 2.) SafAle™ S-33 will leave most of the maltotriose. Conversely, SafAle™ BE-256 consume almost all of it. Furthermore, SafAle™ WB-06 and SafAle™ BE-134 are S. cerevisiae var. diastaticus and will convert dextrins into fermentable sugars.

Esters:

Some specific SafAle™ strains develop a neutral profile, while other yeasts express more fruity flavour. (Table 3.) Mainly SafAle™ BE-256 and SafAle™ WB-06.

Esters

Amyl(Acetate) An ester of acetic acid, pleasant fruity/banana odour, used as a flavouring agent, a paint and lacquer solvent, and in the preparation of penicillin. Also called banana oil.
Ethyl (Acetate) Characteristic sweet, pleasant fruity odour and is used in glues, nail polish removers, and in the decaffeination process of tea and coffee. Ethyl acetate is the ester of ethanol and acetic acid.
Isoamyl (Acetate) Isoamyl acetate has a strong odour which is described as similar to both banana and pear.
Phenylethyl (Acetate) Rose and honey scent and a raspberry-like taste, it is widely used in perfume compositions, from everyday soap and detergent perfumes to fine cosmetic fragrances, room-sprays, deodorants, etc

What Is Glycerol?

Glycerol (C3 H8 O3) is a non-volatile compound which has no aromatic properties, but which significantly contributes to wine quality by providing sweetness and fullness (Ribereau-Gayon et al. 1972). It is the most import by-product of alcoholic fermentation in quantity after ethanol and carbon dioxide (CO2). This is also relevant to beer production, especially with lower abv beers and non-alcoholic beers. Yeast produce a varying level of glycerol during primary fermentation, but with beer, it is usually at low levels and often undetected in the final beer.

Why is Glycerol important?

Glycerol has a favourable impact on beer and wine quality. It is non-aromatic due to its non-volatile nature but can contribute to the sensory properties of beer and wine depending on the concentration. Wines lacking in body can benefit from an increased glycerol production to improve the sensory characteristics. The production of glycerol is also very important to maintain the redox potential of the yeast which is vital during fermentation.

Let’s talk about wine for a minute… Because this is where I learnt how I could instantly manipulate a “thin” beer into a beer with much higher sensory attributes. Wine yeasts, while not really suited to beer, express a very interesting trait. They develop large amounts of glycerol that can greatly impact mouthfeel and body of a wine.

The amount of glycerol usually formed by Saccharomyces cerevisiae in wine varies between 2–11 g /L but normal concentrations are in the range 4–9 g/L. Glycerol production can be controlled by the choice of the appropriate yeast strain. there are studies of the production of glycerol by wine yeast strains, under controlled laboratory conditions (synthetic must 230g/l of sugar (glucose/ fructose), no nutritional deficiencies (300 mg/l of YAN) at 24°C) and mimicking winemaking conditions.

There is a wide range of different production of glycerol depending on the yeast strain. We can classify selected wine yeast into 3 categories: low, medium, and high glycerol producers. At the lowest range, the yeast GHM is at 6.22 g/L and the highest, the S6U at 12.62 g/L. Most selected yeast are found to be medium producers (between 7 and 8 g/L), a few high producers such as Cross Evolution, VRB, CLOS, BC and 43 (between 8.08 and 9.6 g/L). Those with the highest production can be particularly interesting in wines which have lower mouthfeel and structure. It is important to consider the other characteristics of the wine yeast as they might not be suitable for all wines.

Now back to beer!
One thing that is commonly echoed with non-alcoholic beer is the “thin” mouthfeel and body. Something that we have tested and confirmed by ourselves, and various other brewers is that, by adding the commercially available version “glycerine” to a low bodied non-alcoholic beer, it greatly improves the mouthfeel and body of the beer and can sometimes act as a smoother for beers that are overly bitter. You can find more information on our tests here.

What are Thiols, and why are they important?

Thiols, also known as mercaptans, are sulphur-containing organic compounds with a sulphur atom bound to a hydrogen atom. Scientists first identified them in hops in the early 2000s, focusing on three, that winemakers have known about for decades. One, 4-mercapto-4-methylpentant-2-one (4MMP), smells and tastes of box tree, black currant, and ribes. It is also known as 4-methyl-4-sulfanylpentan-2-one (4MSP). Another, 3-mercaptohexan-1-ol (3MH), is often described as exotic, smelling of rhubarb and citrus. And the third, 3-mercaptohexyl acetate (3MHA), is reminiscent of passion fruit and guava. Thiols, along with other compounds such as terpenes and esters, contribute to the enjoyable odours in “hop-forward” beer styles. Although very small amounts of thiols are present in beer, a little bit of these compounds goes a long way toward achieving a hoppy flavour and fruity aroma. Too much of these compounds can lead to off flavours.

In recent years, yeast manufacturers have been able to identify, and release new yeast strains that can unlock, and emphasis thiols bound within the hops that can help improve hop flavour in beers. These stains can greatly improve hop forward beers and deliver higher impact flavours without needing to use large amounts of hops to compensate.

Nitrogen in Beer

Other than sugar, nitrogen is probably the most important macronutrient required for yeast health and growth. Nitrogen deficiency is associated with several fermentation difficulties including stuck and incomplete fermentations, whereas excess nitrogen is related to the production of both off flavours and beer spoilage.

Nitrogen is often assessed by measuring Free Amino Nitrogen (FAN) or to give it its other name Primary Amino Nitrogen (PAN). FAN or PAN assays, test for the concentration of amino acids and small peptides that are utilized by yeast for cell growth and proliferation. Together with ammonia, FAN/PAN makes up what is known as Yeast Assimilable Nitrogen or YAN.

FAN compounds are formed naturally during malting and mashing by the action of protein degradation enzymes on hordein, a protein found in the grain. The level of amino acids available in the wort relies on several variables including grain variety, as well as malting and mashing conditions, but the overall types of amino acids available will be similar among all whole malt worts. Likewise, the specific amino acids taken up by yeast follow a similar pattern during fermentation, although environmental changes can alter this.

Using adjuncts, such as corn and rice, dilute FAN levels in the wort while increasing fermentable sugars. Consequently, high-adjunct worts are nitrogen deficient, and fermentation can be adversely affected, leaving high levels of sugars in the beer. FAN levels in the wort are often regarded as the best indicator of potential yeast growth and are therefore directly related to fermentation efficiency. Yeast need FAN to grow and reproduce, so theoretically the more you have the quicker your yeast will grow, the stronger it will be and the more alcohol your yeast will produce.

Yeast consumes most of the FAN in the first 36-40 hours of fermentation, during its propagation phase. As they do so they can produce a range of metabolic by-products some of which affect flavour and stability of the finished beer.

Yeast Strains with Potential for the Production
of Non-Alcoholic and Ultralow Alcohol Beers.

Beer Strains & Information

Dry or Full-Bodied Beers?

Esters

What Is Glycerol?

Why is Glycerol important?

What are Thiols, and why are they important?

Nitrogen in Beer

Beer Strain Reference Links

Cider & Wine Strain References

Yeast Strains with Potential for the Productionof Non-Alcoholic and Ultralow Alcohol Beers.

Beer Strains & Information

Dry or Full-Bodied Beers?

Esters

What Is Glycerol?

Why is Glycerol important?

What are Thiols, and why are they important?

Nitrogen in Beer

Beer Strain Reference Links

Cider & Wine Strain References

Yeast Strains with Potential for the Production
of Non-Alcoholic and Ultralow Alcohol Beers.