Winemaking in the Classroom 1

1. Winemaking in the Classroom 1 Equipment, Yeast, Fruit & Chemicals Downloaded from seniorchem.com/eei.html

2. Requirements • Fruit, juice, or juice concentrate • Chemicals may include: potassium metabisulphite, tartaric acid, enzymes, bentonite, fining agents • Temperature Control Method for fermentation (air-conditioned room as a minimum) • Yeast • Fermentation Vessels and Equipment • Testing Equipment for: pH, SG, Free SO2, temperature, acidity, alcohol • Siphon for Racking, Filters, Bottles and Closures

3. Fruit/Juice: • Strongly recommend use of grapes/grape product • Possibilities include: • Wine grapes, table grapes, grape juice concentrate, raisins soaked or blitzed in water • Fruit preparation: ideally low solids, but relative high dissolved oxygen • Freshly crushed and pressed juice best option • Also preservative free juices, or can soak raisins (must be sulphite free) • Canned juices are an option also • ‘Cloudy’ juices may work better than filtered juice as they have a higher natural nutrient level

4. Reasons for Preferring Grapes: • Ideal pH range for fermentation (not too high/low) • Sugar ratio 50:50 glucose:fructose • Naturally high levels of tartaric acid (stability) • Better structure to wines • Better balance of acid and flavour • High number of flavour compounds from grapes vs. other fruit

5. Potential Issues with Other Fruit • Use of other fruit may result in negative flavour and structure characters such as: greenness, bitterness, hardness, ‘thin’ acidic or bitter wines • Possible issues with flavour/colour stability, fruit wines often don’t keep well • Usually lower alcohol than grape wine – potential for spoilage is higher • Sugar balance and acid profiles of other fruits may make them less suitable for fermentation • i.e. sweet eating apples: fructose>>glucose – this can cause sluggish ferments

6. Grape Juice Concentrate Kits • Consider as an easy option to get started • Can buy ‘kits’ to make red or white wine including all chemicals required • Less likely to have stuck ferments with a concentrate kit (but not foolproof!) • May be ideal if time is restricted for getting fermentation set up and started

7. All About Yeast • Wine strains best suited (not brewers yeast) • Requirements: • alcohol tolerant to 15% • suited to low pH/low Nitrogen • low VA & H2S production • medium sugar accumulation

8. Where to get yeast Where to buy yeast: Laffort (bulk supplier), Sirromet (comes in 500g packs) many home brew shops sell wine yeast in small packs which may be more suitable Comes in freeze-dried form Care of dried yeast: Cool store or fridge, vacuum sealed, 12 months maximum shelf life. Once opened, seal packet with tape, store in fridge and use within a few weeks

9. Fermentation Equipment • Suitable fermentation vessels: • Beer kegs, glass demi-johns: no taint • Plastic: hydrocarbon pickup, can produce plastic taint in wine • Use fermentation bubblers or silicon bungs • One way seals, or a plastic bag full of sand.

10. Fermentation Equipment (cont) • If your juice contains solids or skins, or is at higher temps: • Initial ferment should be started in a wide necked vessel • Bucket or plastic keg (loosely covered to allow CO2 escape) • Move to a narrow neck vessel once ferment has become less vigorous

11. Ferment Monitoring Equipment • Refractometer – for measuring Brix on juice pre-ferment • Hydrometers: • Baume scale (for juice) • Specific Gravity (for ferment monitoring) • Thermometer or data-logger to monitor temperature • Valenche or Wine Thief for sampling (optional)

12. Sanitation of Equipment Sterilisation (heat) – could rinse/soak clean vessels in boiling water – limited effectiveness, or boil small pieces of equipment Chemical sterilisation – hypochlorite (bleach) – rinse very, very well after Chemical sterilisation – caustic wash followed by acid wash, water rinse Chemical sterilisation – sulphite solution

13. Chemicals Tartaric acid – to adjust acidity of must before or after ferment (can be used for any fruit/juice) Yeast Nutrient – DAP or Fermaid Sugar (if required) – use table sugar Enzyme – to assist with cold settling of high solids juice pre-ferment Potassium metabisulphite or Camden tablets – SO2 preservative and/or sanitiser Bentonite – kaolin clay base used to aid clarification after fermentation (comes in dry form)

14. Processing & Finishing Equipment • Fruit press – for grapes or soft fruit, table top, manual stainless steel • Siphon tubes – clear plastic tubing is effective (silica or PVC food grade) • Filtration options – most are beyond the classroom budget, but gravity filters or small electric filters are available • Bottles and screw-caps or corks

15. Some useful links for businessesthat sell winemaking supplies www.ibrew.com.au12-16 Tonga Place, Parkwood www.homebrewbarn.com325 Gympie Rd Kedron www.uq.net.au/homebrew69 Shore St, Cleveland www.nerangbrewing.com.au 41 Price St Nerang or Shop 9, Oxenford Square Shopping Centre, Old Pacific Highway, Oxenford Many other large home brew shops may have equipment/kits www.winequip.com.au - not in Qld, high quality home winemaking equipment by mail order, well-priced Carlton Glass (Sunshine Coast) www.carltonglass.com.au manufacturer of hydrometers and other wine testing glassware