To expand on what Jim and JohnT are saying: if what your wife likes about chardonnay is the "buttery" flavor, that is typically accomplished in commercial wine by malolactic fermentation, which shouldn't be done to a kit.
But, you can do something else: sur lie and batonnage. All you need is a spoon.
I have a chardonnay bulk-aging and had intended to do sur lie and batonnage during the process but didn't get a chance to do so.
Basically, the sur lie process is leaving the wine on the fine lees, and batonnage is stirring. They are both ways to get close to a buttery commercial chardonnay with a kit. In practice, that would mean you'd rack part of the way during fermentation, maybe halfway, and leave behind the gross lees; then you'd let the balance of fermentation happen on the lees and stir the fine lees into the wine daily, or as often as your time permits.
Here's info:
Why use lees?
When yeast cells die their cell walls breakdown, gradually releasing such compounds into the wine as polysaccharides (e.g. glucose), amino acids (and peptides), fatty acids, and mannoproteins. The compounds released can influence the structural integration of the wine in terms of phenols (including tannins), body, aroma, oxidative buffering and wine stability.
At the end of alcoholic fermentation, yeast cells autolyse. Yeast autolysis is a slow process involving hydrolytic enzymes which act to release cytoplasmic (peptides, fatty acids, nucleotides, amino acids) and cell wall (mannoproteins) compounds into the wine.
The primary reasons for sur lie ageing are usually based on stylistic goals: to enhance the structure and mouthfeel of a wine, give it extra body (an impact of polysaccharides on astringency), and increase the aromatic complexity, flavour/aroma depth and length. Lees also absorb oxygen, assisting in maintaining a slow and controlled oxidation during maturation. Lees stirring can increase the release of yeast compounds into the wine bulk. Stirring can result in a creamy, viscous mouth feel, and can enhance flavour complexity.
Some of the compounds from broken down yeast cells also contribute to wine in the following ways:
•polysaccharides contribute a roundness and volume to the palate
•mannoproteins can bind with anthocyanins and tannins to increase colour stability and decrease astringency
•the nutrients released from the dead yeast cells assist the growth of malolactic bacteria
•increased palate length, attributed to the late release of particular volatile compounds in the polysaccharide network of the fruit and yeast
•they can assist in protection from oxidation of particular fruit aroma compounds.
•the process of proteolysis, whereby proteins are hydrolysed to amino acids (which can act as flavour precursors, possibly enhancing flavour complexity) and peptides (which travel through the yeast cell walls causing an increase in nitrogen content).
•dead yeast liberate esters, particularly fatty acids with sweet/spicy (fruity) aromas (such as ethyl hexanoate and ethyl octanoate); this coincides with the time when fermentation esters (such as isoamyle acetate and hexyle acetate) experience hydrolysis, resulting in combined sweet/spicy/fruit aromas
•the release of amino acids and nucleic acids can enhance flavours and complex aromas, particularly at the end of the palate
•they yield a sweetness when binding with wood phenols and organic acids
•they modify wine esters and wood aromas
•they provide a natural fining, reducing more yellow colours in whites
•they improve protein stability (current research suggests that lees do this by producing an extra mannoprotein (polysaccharidic molecules which constitute ~35% of the yeast's cell) which prevents polymerisation of tannins, pigments and volatiles; and more of this compound is released when the temperature is increased, and with greater contact time and lees stirring frequency)
•they can assist potassium bitartrate stability, since mannoproteins act as potassium bitartrate crystal inhibitors
•they can reduce colour: the more yeast cell surface area, the higher the absorption and subsequent loss of colour
Lees and oak
Lees can help remove harsh oak phenolics and assist in integrating oak flavours. Lees substances (such as polysaccharides) bind with free ellagic tannins, modifying wood tannin astringency and thus reducing the amount of perceived tannins.
Additionally, lees substances can bind with wood-derived compounds such as vanillin, furfural and methyl-octalactones, modifying the oak aromas present in the wine.
Lees and MLF
Lees contact is often run parallel with malolactic fermentation. The goals of each technique are similar in some respects (e.g. creating a wine which is generally perceived as softer). Lees in the presence of MLF tends to lead to lower diacetyl ("buttery") concentrations, since the yeast metabolise the diacetyl to the non-aromatic compounds acetoin and 2,3-butanediol.
Lees control: types and quantity
Lees stirring is usually conducted on "fine lees" and not "gross/heavy lees".
Heavy lees can be defined as comprising of particles that are typically 100 microns to 2 millimetres. They tend to settle within 24 hours (without pectin). This definition certainly includes fruit debris. Fruit debris can impart off and herbaceous aromas and flavours and can combine with SO2 blocking its antimicrobial and antioxidant properties. Heavy lees may yet further be defined as those substances continually forming in wine. In this case they may also comprise of yeast, bacteria, precipitated tannins/colouring matter/colloids, and particles formed from fining treatments. These can release undesirable bitter substances into the wine.
Light lees comprise of particles that are typically of size one micron to a few tens of microns. They tend to remain in suspension for longer than 24 hours after they have been agitated. They are comprised of yeast and lactic bacteria (produced towards the end of alcoholic fermentation and malolactic fermentation, respectively). Light lees is favoured for sur lie and stirring, but still poses risks of producing reductive aromas/flavours if inappropriately managed.
Separating the gross/heavy lees from the must provides the first opportunity to control the content of lees in the must/wine (the process is called "débourbage" in French). The first racking following alcoholic fermentation gives an opportunity to control the amount of fine lees to be used for sur lie ageing. Choosing the timing of heavy lees separation is an important aspect of lees management. Many winemakers make a judgement on the amount of lees to include in the bulk wine (or whether to include any at all) based on its taste (whether "clean" or "dirty" smelling) at either of these two important stages.
Lees and yeast
The influence of the compounds from broken down yeast cells depends on the individual yeast strains (though the release kinetics of mannoproteins appears to be independent of yeast strain). Different results should therefore be expected from different yeasts. While this influence is not important as other features (such as lees quantity and type control), it may still be taken into consideration.
Lees stirring (Bâtonnage)
Bâtonnage is the French term for stirring the settled lees back into the wine.
Method of stirring
Any method which redistributes the lees thoroughly provides an adequate method of stirring, but different methods contribute differently to wine.
On a moderate scale (such as a single barrel), this can be achieved by the use of a steel rod with a paddle at the end which can be placed in the tank or barrel and spun with an electric drill attached.
On a small scale, a food turntable can be used which allows the process to be controlled externally.
It is important to note the oxygen exposure that each method exerts on the wine, since this will significantly impact wine development.
Intensity and frequency
Lees should be stirred thoroughly, bringing all lees into suspension. The more lees there is, the more frequently stirring should be conducted.