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Winemaking Fermentation Techniques and Mouthfeel: An ICV PerspectiveDominique DELTEIL
Presentation plan • ICV Guideline for Mouthfeel Management • The Sensory Tools : sensory method, database, reference profiles • Chemical background of ICV sensory descriptors • Enzymes, Yeast, Nutrients and Cap Management : ‘Good Practices’ to manage Mouthfeel Profile • ICV Practical Consulting Testimony for : • Grape ripening • Enzymes, • Yeast, • Nutrients, • Cap Management
First Key Point in Guideline : a tool to measure the progress and guide the process
Let’s try to speak the same language when talking about mouthfeel Otherwise, we are no longer referring to consulting anymore. It is just a ‘guru’ attitude that is out of ICV Consulting Good Practice Guideline.
What is ICV Mouthfeel ? • A Quantified Descriptive Sensory Analysis Profile (QDSAP) • With 6 descriptors : • A precise procedure with : • A fixed and measured order • A fixed rhythm, in order to standardize the wine/saliva/mucosis interactions, and therefore improve repeatability
1 2 3 4 5 6 The 6 Descriptors of ICV Mouthfeel Profile (Red wines) Measured Order of the 6 descriptors
Some examples of Mouthfeel Profiles A quick glance to form a picture of the different profiles possible
ICV Mouthfeel of a so-called « round, big, good tannin » or Ultra Premium Red wine 1 2 3 4 6 5 High foremouth sensations and low aggressive final sensations
ICV Mouthfeel of a so-called « thin, hollow, green tannin » red 1 2 3 4 6 5 Low foremouth sensations and high aggressive final sensations
ICV Mouthfeel of a so-called « tannic, over-extracted » red 1 2 3 4 6 5 Low foremouth sensations and high mid-palate + high final aggressive sensations
+ ICV Mouthfeel of a so-called « Brett- killed great Cab » red 1 2 3 4 6 5 Very dry and bitter in the back of the mouth + metallic sensations
From our database : 1) Conform, 2) Limit and 3) Non-conforming Profiles Quick glance to have a picture of the different profiles possible
Consulting Guideline: it is not a question of good / evil, but a conform/non conform commercial position
ICV Sensory Positionning of Commercial Wines.Ultra Premium Reds. Structured scale with 4 levels. From : Delteil, 2001 Mouthfeel Conforms Mouthfeel on the Limit Mouthfeel Non-conforming Easy-to-remember profiles that can be referred to during maceration or aging
A Chemical Background of ICV Sensory Descriptors Volume & Bitterness
In the following slides: « + correlation » means: same trend « - correlation » means: contrary trend (+) doesn’t mean « good » (-) doesn’t mean « evil » Let’s leave « good » and « evil » judgements to consumers and wine writers!
Foremouth Volume: main compounds involved • Ethanol: + (up to 14%vol) • Polysaccharides from grape, yeast, bacteria & oak: + • Sugar: + • Acids, salts: + (until a certain level and according to other elements) • Glycérol ? (a myth… just a short sweet peak in the mid-palate and a higher dryness in the finish) • Volatile compounds with ripe, sweet smell: + (the portion of those compounds that stays in solution in the wine has a smooth impact on the mouth mucosis). • Sulphur off-flavours: - (the portion of these compounds that stays in solution in the wine has an agressive and « cold » impact to the mouth mucosis).
Foremouth Volume: sensory interferences • Influence of all the other descriptors: • A physiological influence (the sensation step of ASDQ): for example, a high acidity interferes during the measurement of the Foremouth Volume, usually lowering the sensation (of what we perceive) • A psychological (the translation step of ASDQ): for example, herbaceous mouth aromas pushes to lower the Volume mark, even when the sensation was the same • General trend: Foremouth Volume and Bitterness have a negative correlation (when Volume is high, generally bitterness is low)
Bitterness: main compounds involved • Ethanol: + (amplifies the impact of bitter compounds) • Sugar:- • Grape Tannins and Oak Tannins: + • Acids (mostly the malic acid) : + • Sulphur aromas: ++ • Certain volatile compounds (those that give ripe, fruity, spicy aromas) : - (physiological and psychological reasons) • Yeast in suspension (wine just stirred): + • Polysaccharides from grape, yeast, bacteria or oak: -
Bitterness: sensory interferences • Strong influence of • Acidity: +, • Sulphur, chemical and herbaceous aromas: +
Winemaking challenges • Analysis of the situation: • High risks of sulphur aromas produced by the yeast because of low nutrients and high osmotic shock: producing dryness and bitterness sensations • High ethanol enhancing dryness and bitterness • Strategy to follow: • Developp and stabilize as much as possible all elements that limit dryness and bitterness: polysaccharides and compounds with ripe aromas • Limit as much as possible the production and stabilization of all agressive (astringency and dryness) and bitter compounds • Explore all possibilities and make consistent choices throughout the process
Ageability Ripening, Enzymes, Yeast, Nutrients and Cap Management effects on Mouthfeel
Chardonnay simplified profiles • Complete maturity : • Goals to be reached to achieve return on investment on strong enological potential vineyard blocks. • To elaborate higher end wines with foremouth volume, aromatic complexity, good length. • Ability to be fermented and aged in barrel. • Minimum commercial maturity • Goals to be reached for mid range vineyard blocks. • Fruity wines, without agressive mouthfeel.
Maceration enzymes: main influences (1) • Direct hydrolysis of polysaccharides (pulp and skin): early, greater level of stable macromolecules in the colloidal network, and then more interesting interactions with ripe aromas • Early liberation of the sensorically interesting tannins: the hydrophiles ones. In ripe grapes, they are already integrated in a polysaccharide colloidal matrix: early stabilization in a less sensory aggressive form (medium-length chain)
Maceration enzymes main impacts (2) • Direct action on limiting sulphur off- flavour production during fermentation: a clear experimental trend (Why? Earlier yeast access to certain nutrients? Early interaction between sulphur compounds and grape polysaccharides?) • Indirect action on sulphur off-flavours and herbaceous aromas: easier and more efficient racking directly after maceration, with good and early elimination of heavy ‘vegetal’ lees
Effects of maceration enzymes on mouthfeel profiles in reds. ICV Guideline based on 15 years experimentation and experience No Maceration Enzymes Maceration Enzymes + cleaner aromas & more stable colour
Yeast main possible impacts: selected enological yeast variability (1) • Better resistance to juice stress (high sugar, very low nutrients, high ethanol) • Less production of sulphur compounds • Less production of VA • Less space left for Brettanomyces and Co developpment at the end of fermentation • Better answer to modern demands • Less SO2 production, giving a better sequence of malolactic directly after alcoholic fermentation
Yeast main possible impacts: selected enological yeast variability (2) • More mannoprotein produced during active fermentation and during aging with light lees: • Earlier development of a stable wine colloidal network (polysaccharides + pigments + tannins) • More and early interactions with ripe aroma compounds from the grapes and from the yeast (more stable and sweeter aromatic expression) • Better sensory integration of very high ethanol concentration
Possible trends between selected yeast in reds. ICV guideline based on 20 years of experiments and experience 70’s yeast selection made on basic parameters Selection made to achieve today’s Ultra- Premium wine conformity + richer, cleaner aromas & more stable colour + limiting Atypical Aging in whites
Yeast Nutrients possible impacts : nutrients containing inactivated yeast • Better complete nutrient and yeast membrane status: • Less production of sulphur compounds (because there is no enhancement of amino acid starvation in nitrogen-depleted juices : the opposite of the situation when only ammonia salts are added) • Less production of VA • Release of yeast mannoproteins: • Balance the chemical aromas and dryness due to the assimilation of ammonia salts • Better sensory integration of very high ethanol concentrations
Effects of Yeast Nutrients on Mouthfeel profiles in reds. ICV guideline based on 10 years of experiments and experience DAP additions Fermaid additions + riper, cleaner aromas
Délestage. Preparation Délestage can be started as soon as the cap is formed. Délestage is also nteresting during cold soak (with little air addition)
Délestage. Step #1 Notes: 1= yeast at the bottom of the tank 2= fermenting juice not in contact with the pomace 3= pigment and tannins concentrated juice below the pomace : low extraction, low stabilization 4= juice bathing the pomace 5= emerged pomace : no juice contact First tank is completely drained. An open jet in a bucket allows a true juice oxygenation : 2 to 4 mg/liter dissolved oxygen Some other systems can give a similar efficiency in adding dissolved oxygen
CO2 Délestage. Step #1 (cont.) Complete draining of the first tank is a key point of délestage. The most concentrated juice (the juice just below the cap) is renewed and oxygenated. A pumping over does not renew this juice. A punching down renews it, but does not oxygenate it.
Délestage. Step #2 Complete draining of the cap achieves the diffusion goals : extracts the most interesting grape macromolecules. Complete aeration brings stabilisation, tannin « coating / enrobage » and sulfur off-flavor management
Délestage. Step #3 The return of the juice is done with high flow and low pressure (flooding), to avoid mechanical action on the cap. It is not necessary to look for a complete cap bathing
Délestage. Step #4 When the cap stays together, it percolates through the juice or the wine. In other situations, it « melts » in the juice giving also excellent juice / cap exchanges, without violent extractions
Early Délestage main impacts (1) • More liberation of grape polysaccharides (pulp and skin): early and higher level of stable macromolecules in the colloidal network, and also greater interaction with ripe aromas • Early and intense liberation of the most sensorically interesting tannins: the hydrophilic ones. In ripe grapes, they are already integrated in a polysaccharide colloidal matrix: early stabilization in less sensory agressive forms (medium length chain)
Early Délestage main impacts (2) • Direct action on limiting sulphur off- flavour production during fermentation: complete yeast stirring, oxygen available for all yeast, physical stripping of early production of H2S
Effects of Délestage on Mouthfeel profiles in mediterranean reds. ICV Guideline based on 10 years experimentation and experience Only pumping over, 15 days maceration 7 Délestages during a 15 days maceration + riper, cleaner aromas & more stable colour (with the same analytical amount of polyphenols)
Common sense statements • A well positioned wine answers its segment standards as soon as released : a minimum drinkability. • The « good to drink starting 2015-2030 » is an ultra small niche position.
Common sense statements (2) Ageability is a segmented concept : • mid priced wine from rather high yield vines : • get the maximum quality attributes at release • keep a certain quality level through the whole shelf life • high priced wine from highly concentrated grapes • get an acceptable level of drinkability at release • develop positive attributes through time