small lot fermentation method

0.21 MB·

by  Anne.Lord

Fact Sheet
WINEMAKING
WINEMAKING

Small-lot fermentation method for smoke-exposed grapes

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com.au/itm/Art-

Vintage-Aqua-

Navy-Set-Home-

Decor-Cotton-

Linen-CUSHION-

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Assessing the potential for grapes to made from grapes that have been exposed
produce smoke-affected wine to smoke.
CASE-18-
When vineyards and grapes are exposed to
The AWRI recommends that grapes are also
smoke this can result in wines with
analysed for volatile phenols and glycosides
undesirable ‘smoky’ sensory characters. The /at2 the0 sa1me 3tim3e th7e s4ma9ll-lo6t fe6rme9nta2tio?n
compounds in smoke primarily responsible
is started. This will allow the chemical results
for these characters are free volatile phenols.
and the sensory assessment to be used to
These can be absorbed directly by grapes pmatke= haLrveHst de_ciDsiones. faultDo
and bind to grape sugars to give glycosides
that have no smoky aroma. Aroma This fact sheet sets out all the steps for
assessment of grapes or juice will therefore mcondauctiinng a_ sm1al5l-lo&t fermveantartio=n. &A flohw
not give a good indication of the potential chart is also provided on the final page
impact of smoke exposure on the resultant (Figure 1).
wine. ash=item2ee0a6
When to sample
During fermentation or wine storage the
This procedure can be used as soon as
glycosides can break apart, releasing volatile 6474
grapes are ripe enough to be able to be
phenols into the must or wine, allowing the
fermented, but it is preferable to conduct the
smoky flavour to be perceived. It is therefore
ferments about two weeks before harvest.
recommended that winemakers conduct
The later this procedure is used, the more
small-lot fermentations, followed by sensory
reliable the indication of smoke exposure will
assessment, to gauge the potential risk of
be. It is best to plan in advance to ensure the
smoke characters being perceived in wine
small-lot fermentation is conducted in time
to be used to support harvest decisions.

Updated January 2021
Fact Sheet
WINEMAKING
WINEMAKING

Grape sampling pectinase solution and dilute further into
25 mL of water and then tip the whole lot
It is important to ensure that a http://www.ebay.
evenly across the grapes. Mix in
representative sample is collected from the
thoroughly with potato masher.
entire vineyard. Refer to the AWRI grape
sampling fact sheet for more details. • Acddo DAmP. M.eaasuure o/uit tapmprox/imAaterly t-
6 mL of the 10% DAP solution and tip the
Weigh out approximately 5 kg of berries
whole lot evenly across the grapes. Mix in
stripped off grape bunches and transfer
thoroVughilny wtitha pogtateo m-aAsheqr. ua-
them into a clean open container; for
***Important – Do not mix SO and
example, a 10 L stainless steel bucket, a large 2
pectinase solutions together prior to
pot or a food grade plastic storage container. Navy-Set-Home-
addition ***
A loose- fitting lid or cover can be used to
allow ferment gas to escape and prevent
• Adjust acidity to around pH 3.4 (if
contaminants or vinegar flies from entering. Decor-Cotton-
required). For every 0.1 pH decrease
required, add 3 g of solid tartaric acid or
Fermentation on skins
30 mL of a 10% tartaric acid solution. For
The AWRI recommends that when Linen-CUSHION-
every 0.1 pH increase required, add 1.5 g
conducting small-lot ferments for the solid potassium bicarbonate or 15 mL 10%
assessment of smoke risk the fermentation potassium bicarbonate solution. Mix in
COVER-PILLOW-
should be conducted on skins, regardless of thoroughly with potato masher.
whether the grapes are red or white. This
Note that due to the use of hand crushing,
provides an opportunity for maximum
the addition amountCs in AthisS prEoce-du1re8 are-
extraction of smoke taint compounds, if
based on a low 600 L/T extraction rate, or
present, and therefore gives a ‘worst case around 3 L of juice expected from 5 kg of
scenario’ result for white wines. Winemakers /fru2it. 0 1337496692?
may also choose to also conduct a
See ‘Preparation of solutions’ for instructions
fermentation off skins for white grapes,
pon tho=w tLo pHrepa_reD thee reqfuaireud solltutDionso.
producing a wine for sensory assessment
that reflects a more realistic outcome for a
Yeast preparation and inoculation
white wine fermentation.
m• Adad 5i0n m_L o1f ch5lor&ine-vfreae wrat=er (&suchh as
Must preparation and additions reverse osmosis treated, distilled or Milli-
Q)to a clean drinking glass and heat in a

• Crush the grapes using a potato masher.
amsicrhow=avei tto ea temmpe2ratuere eof 308-4a0oC6.
• Take a sample for Baume, pH and TA Dissolve 2.5 g of sugar (raw or white) in
measurement. the warm water. Weigh out 1 g yeast and
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sprinkle onto the water. Gentle mixing
• Add SO . Measure out approximately
2
may be required to ensure all the yeast is
1.5 mL of the 10% SO solution into about
2
properly wetted. Leave for 10 minutes to
25 mL of water and then tip the whole lot
allow the yeast to rehydrate.
evenly across the grapes. Mix in
thoroughly with potato masher.
• Add pectinase. Measure out
approximately 1.5 mL of the 10%

Updated January 2021
Fact Sheet
WINEMAKING
WINEMAKING

• Make sure the must is around 20oC (ideally Drain and press
20-25oC). Add 50 mL of must to the 50 mL
•h Wtetigph an: /em/pwty sewalabwle c.oentabinera (aty .
of hydrated yeast and leave for 10
least 3 L volume).
minutes, before adding the entire
contents of the yeast culture to the • Drain the ferment through a sieve into the
com.au/itm/Art-
fermenter. This is a yeast addition of container, press the solids against the
300 mg/L. Yeast inoculation day is sieve, then re-weigh the container to
considered day 0.The time for the yeast determine the wine volume
Vintage-Aqua-
rehydration procedure should not exceed (assuming 1 kg=1 L)
40 minutes.
End of ferment additions
• Place fermenter in an area that is between Navy-Set-Home-
SO addition:
20 and 25oC (e.g. winery laboratory). 2
• Using the determined wine volume, add
Fermentation management
0.8 mDL/Le of c10%o SOr- soClutoion ttot thoe wnine-
2
The ferment will take about five days. and mix thoroughly.
Daily tasks:
Copper sulfate addition:
Linen-CUSHION-
• Mix the ferment three to four times per
• Using the determined wine volume, add
day by plunging with a potato masher or
approximately 0.4 mL/L 0.2% CuSO
stirring with a long handled wooden 4
CsolOutionV. ItE is ERSSE-NPTIAIL Lto LaddO thisW -
spoon – try to break up and submerge the
DROPWISE to the wine while mixing
cap.
thoroughly.
• Smell the ferment for any hydrogen CASE-18-
Seal the container and place in refrigerator at
sulfide (H S) or ‘eggy’ aroma. If observed,
2
4oC for 48 hours to settle out solids.
add 3 mL of 10% DAP solution (100 mg/L
of DAP). /Ra2ck0, de1ca3nt,3 an7d b4ott9le 6692?
• On day 2, measure out approximately
• Rack or transfer the clear wine using a
6 mL of 10% DAP solution and tip the
pstip=honL hHose _intDo tweo 7f50a muL orl tfoDur o
whole lot evenly across the grapes. Plunge
375 mL clean wine bottles, filling them as
to mix thoroughly.
much as possible to decrease headspace.
• After five days of fermentation, take a mSeaal iwnith _a s1cre5wca&p. var=&h
sample and test for residual sugar using
• Wine can now be subjected to sensory
an AimTab or Clinitest.
assessment for the presence of any smoke
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• If the AimTab/Clinitest reads <2 g/L sugar, taint.
then proceed to drain and press, as

described below. If the Clinitest reads 6474
>2 g/L sugar, then ferment for an extra
day and recheck residual sugar. Repeat if
necessary, then proceed to drain and
press.
• Do not exceed seven days on skins post
inoculation even if sugar >2 g/L.

Updated January 2021
Fact Sheet
WINEMAKING
WINEMAKING

Preparation of solutions for additions 10% diammonium phosphate (DAP) solution
(store at room temperature, expires after
Use reverse osmosis (RO) treated water, http://www.ebay.
3 months)
distilled water or Milli-Q water to prepare the
required solutions. • Weigh 10 g DAP into a clean bottle (~100
mcLo). m.au/itm/Art-
10% SO solution (store at room temperature,
2
expires after 2 weeks) • Add 80 mL of warm water and mix until all
the crystals dissolve.
• Weigh 20 g of potassium metabisulfite Vintage-Aqua-
(PMS) into a clean bottle (~100 mL). • Top up with water to a total volume of
100 mL.
• Add 80 mL of water and mix until all the
Navy-Set-Home-
crystals dissolve. 2% copper sulfate – STOCK solution (store in
refrigerator, expires after 1 year)
• Top up with water to a total volume of
100 mL. ***Do DNOTe adcd tohisr st-oCck sooluttitono ton win-e
• Weigh 2 g copper sulfate into a clean
10% pectinase solution (store in refrigerator,
bottle (~100 mL).
expires after 2 weeks)
Linen-CUSHION-
• Add 80 mL of water and mix until all the
• Measure 10 mL of liquid pectinase into a
crystals dissolve.
clean bottle (~100 mL).
COVER-PILLOW-
• Top up with water to a total volume of
• Top up with water to a total volume of
100mL.
100 mL.
0.2% copper sulfate –C WOARKSINGE so-lu1tio8n - -
• If using powdered pectinase, follow
(store in refrigerator, expires after 3 months)
manufacturer’s instructions then dilute as
above. • Take 10 mL of the stock solution and add
/201337496692?
to 100 mL of water in a clean bottle
10% tartaric acid solution (store at room
(~100 mL).
temperature, expires after 3 months)
pContt=actL H_DefaultDo
• Weigh 10 g of tartaric acid into a clean
bottle (~100 mL). For further information regarding this
procedure or assistance with smoke taint
• Add 80 mL of water and mix until all the main_15&var=&h
please contact:
crystals dissolve.
AWRI helpdesk
• Top up with water to a total volume of
ash=item2ee0a6
100 mL.
Phone [phone] Fax [phone]
10% potassium bicarbonate solution (store at
Email [email protected]
room temperature, expires after 3 months) 6474
• Weigh 10 g of potassium bicarbonate into Website
a clean bottle (~100 mL). http://www.awri.com.au/industry_support/
• Add 80 mL of water and mix until all the
Address Wine Innovation Central Building,
crystals dissolve.
Corner of Hartley Grove & Paratoo Rd,
• Top up with water to a total volume of Urrbrae (Adelaide), SA 5064
100 mL.

Updated January 2021
Fact Sheet
WINEMAKING
WINEMAKING

Weigh 5 kg subsample into appropriate size vessel
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DAY 0 Operations
Plunge 20 times
before taking a
Crush/squash grapes using hand or potato masher
50 mL sample for com.au/itm/Art-
pH, TA, Be
Add SO (50 mg/L) as 10% SO solution = 1.5 mL/V5 kg.i Pnlunget. age-Aqua-
2 2
Add pectinase: as 10% solution 1.5 mL/5 kg (dilute further Additions:
into 25 mL water). Plunge. The crush SO addition is based
2
Add DAP (200 mg/L) as 10% solution = 6 mL/5 kg – Plunge. on a 500 L/t extraction
Navy-Set-Home-
rate (2.5 L/5 kg)
ALL other must additions are
based on a 600 L/t extraction
Decor-Cottratoe (3 nL/5 k-g)
Adjust pH to 3.4 – as required using 10% tartaric acid to acidify or
10% potassium bicarbonate to deacidify. Plunge
Linen-CUSHION-
Day 0: Inoculate Yeast @ 300 mg/L = 0.9 g yeast/5 kg
Ferment on skins between 20 anCd 25oOC VER-PILLOW-
Plunge/stir ferments 3-4 times per day CASE-18-
Check Baume each day after first plunge
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Day 2: Add DAP: 200 mg/L as 10% solution = 6 mL/5 kg – Plunge
pt=LH_DefaultDo

Press back into original Check residual sugar with
fermenter or 4-5 L container Day 5: Press/sieve off skins AimTab/clini test or G+F daily
with a sealable lid main_15&vaurntil= dry &(<2 g/hL)
Weigh press volume where 1 kg = 1 L

When sugar dry (<2 g/L) – End ofa fermsenht add=itionis tem2ee0a6
Add SO2: 80 mg/L as 10% SO2 solution = 0.8 mL/1 L Take required volume of
Mix thoroughly, then: CuSO and add to 10 mL of
4
Add CuSO: 0.2 mg/L Cu2+ as 0.2% CuSO = 0.4 mL/1 L RO/distilled water for
4 4 6474
Added DROPWISE to mixing vessel ***Critical step*** dropwise addition to wine.
Seal lid and place in fridge/cool room to settle

After two days of cold settling Sensory assessment panel
Clean rack to fill 750 mL bottles for sensory assessment

Figure 1. Steps in the small-lot fermentation method

Updated January 2021