Olives
Olive Production Manual
Louise Ferguson, G. Steven
Sibbett, and George C. Martin
Classification
• Family - Oleaceae
– Genera
• Fraxinus (ash)
• Ligustrum (privet)
• Syringa (lilac)
• Olea (olive)
Olea europaea
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Long lived evergreen trees
Wood resists decay
Top dies - stock sprouts
Roots only 3 - 4 ft (1 m) deep
Dense foliage, poor light penetration,
cascading multiple branches, heavy
fruit on terminals
Leaves
• Thick, leathery, oppositely arranged
• Each leaf grows for 2 yrs
– Spring abscission in 2 to 3 years
• Stomata on lower surface only
– nestled in peltate trichomes
Cultivars
• Ascolano 9 gm / 18.8% Blk Grn
• Manzanillo 5 gm / 20% Fr, Blk, Oil
• Sevillano 13.5 gm / 14.4% Blk, Grn,
SpGm
• Barouni 7.4 gm / 16.5% Fr Blk
• Mission 4.1 gm / 21.8% Blk Gr Oil
Manzanillo
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Most widely planted
Most popular for canning
Low spreading 15 - 30 ft.
Rooted Stem cuttings
Not tolerant to cold
Olive knot - Verticillium wilt
Sevillano
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Second most popular
Spreading 25 - 35 ft tall
Trained low for easy harvest
Largest fruit in California
Grafting 1 yr rooted cuttings
Somewhat resistant to cold
Bruises easily
Ascolana
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Rounded shape 20 - 30 ft tall
Bruises easily
Only 3 % of acreage in CA
Canned ripe olives
Fairly resistant to olive knot
Mission
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From Mexico in 1769, not Italy
Tall upright, 40 - 50 ft
Topped to facilitate harvest
Small, low 6.5 : 1 fruit-to-pit ratio
Rooted cuttings
Trees survive 8oF
Mission Harvest
• Picked green - Spanish Green
Processing because they are late and
need to avoid frost.
• Red coloration - Ripe olive processin
• For oil because of high (21.8% oil)
• High monounsaturated fatty acid
Barouni
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From Tunisia in 1905
Small tree 15 - 25 ft. spreading
Large fruit, low fruit to pit ratio
Resistant to cold
For fresh use - process quality low
Used for black-ripe table olives
Flowering
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Summer 2000 - Induction in veg buds
Nov. 2000 - Floral induction
Winter 2000 / 2001 - Chilling
Spring 2001 - Flowers open
Chilling is Critical
• Optimum Flowering if chilling temps
– Maximum 60 to 65oF
– Minimum 35 to 40oF
• Poor flowering if
– Constant 55oF
• No flowering if
– No temp > 45oF or < 60oF
Influence of Leaves
• Very little dormancy
– Veg. Buds grow at or > 70oF
• Inflorescence formation
– Requires leaves on fruiting shoots
– Thus, prevent defoliation
• Hot winds can defoliate
Flower Buds
• Abnormally cold spring temps
– Detrimental to flower buds
• Floral differentiation 8 - 10 weeks
before May bloom
– Irrigate to prevent stress
– Start season with moist profile
• Playing catch up will not do
Stress
• Causes predominance
– Of male flowers
– Why?
• Girdling can increase flowering
– Danger of Olive Knot
– Not a problem in Israel
– Root reduction
Pollination
• Monoecious
• Flowers borne axially along shoot in
panicles
• Self and cross pollination occurs
Fruit Set
• 500,000 flowers per tree
• Need maximum of 10,000 fruit (2%)
– 98% abscise in 14 days
– Goal is 3 tons per acre yield
• Sometimes insufficient perfect
flowers to set full crop
• Need 10% set if inflorescence limited
Fruit Formation
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Embryo development
Mature ovule (seed)
Mature ovary (fruit)
Requires rapid pollen growth
– Delays caused by cool temperature
• Parthenocarpic fruit (shotberries)
Sigmoidal Fruit Growth
• Endocarp (pit) enlarges to full size
and hardens in 6 weeks
• Endosperm (liquid to solid)
• Embryo development
• Embryo maturity (September)
Maturation
• Gradual growth
– Mesocarp (flesh)
– Exocarp (skin and peel)
• Color change (harvest index)
– Green  straw (optimal)  Red
(maybe)  Black (unacceptable)
Harvesting
• Profit or loss depends on accuracy
of harvest in October
• Delaying harvest = heavier fruit
(more valuable)
• Delaying too long = black fruit & frost
damage
• Oil content increases in January
Fruit Thinning to Avoid
Alternate Bearing
• Hand thinning
– Both hands - heavy rubber gloves
– Strip fruit while leaving leaves
• Leave 6 fruit / foot of twig
• Complete 3 weeks after full bloom
• Effective but not cost effective
Thinning by Pruning
• Prune more heavily on “on” years
• Prune more lightly on “off” years
• However, not cost effective
Chemical Thinning
• NAA effective but must treat prior to
knowledge of crop size
• Treat 12-18 days after full bloom (FB)
• Apply 10 ppm for each day after FB
– 15 days after FB = 150 ppm
– Dilute spray (300 - 400 gal water
per acre
Thinning Ornamental Olives
• Olives in landscape are more
desirable if all the fruit are removed
• Use 200 ppm 2-3 days before FB
– Use second spray 1 week later
• Large trees require power sprayer
– 10 - 15 gal per tree
• Detrimental if temperature > 100oF
Processing Olives
• Types
– Black-ripe (BR) - 99% in CA
– California-style green
– Spanish-style green (<1%)
• Pickling - process of adding lactic or
acetic acid
Chemical Composition of
Ripe Mission Olives (%)
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Water
Brix
Oil
Sugars
Protein
Mannitol
55.0
13.1
21.4
4.6
1.7
4.4
Oleuropein
• A glucoside (bitter factor in fresh
olives)
• Destroyed by dilute alkali at room
temperature
• Remove alkali (1 - 2% lye) and
bitterness does not return
Pigments
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Anthocyanins are major pigment
Increases until fruit is ripe
Decreases in overripened fruit
Light increases formation
10 times more anthocyanin in fruit
ripened in light vs dark
Salt Free Storage
• Acidulant solution
– 0.67% lactic acid
– 1.00% acetic acid
– 0.30% sodium benzolate
– 0.30% potassium sorbate
Traditional Brine System
• Concrete or wooden tanks
• Capacity - 20 tons
• 5.0 - 7.5% NaCl
– 20 - 30o Salometer
– Saturated solution - 26.5% salt =
100o on Salometer
Storage Containers
• Open-top redwood tanks 5x6 ft
• Holds 2.5 tons of olives
• Polyethylene 6 mil plastic prevents
contact between olives and inside of
tank
• No fermentation in this system
• Flavor better than in brine
California Style Black Olives
• Paraffin or plastic lined 20 T tank
• Four overhead pipes
– Water
– Dilute dye
– Dilute brine
– Compressed air
Lye (NaOH) Treatment
• 3 - 5 applications of 0.5 - 1.5%
• Better color by
– Reducing lye concentration
– Increasing treatment numbers
– Reducing duration
Color Formation
• Lye helps
– Natural phenolic compounds to
oxidize and polymerize
– Causing formation of black
pigment
– Provided aeration is present
Calcium Helps Fix Color
• Color formation most rapid at 8.0 to
9.5 pH
• Retention better in hard water
• Ca(Cl)2 (0.1 - 0.5%) improves color
retention
Lye Removal
• Lye removed by changing water in
tanks at least twice daily
• Solution stirred frequently with
paddles of compressed air
• Lye removed in 3 - 4 days
Canning
• 7.0 - 7.5 pH at time of canning retains
color
• Packed in C-enamel lined cans
• Filled with 2 - 2.5 % salt brine
• Cans exhausted at 199 to 205oF for 5
min to reach 170oF or higher
Finish Canning
• Rebrined and sealed at 170oF in a
double seamer
• Olives in glass containers processed
in retort for 70 min. at 240oF
Spanish-Style Pickled Green
Olives
• Fruit reaches full size but harvested
before color changes
• Promptly placed in shallow paraffin or plastic-coated concrete pickling
vats
Lye Treatment
• Dilute lye (1.25 - 1.75%) at 54 - 70oF
penetrates 3/4 way to pit in 8 - 12 hrs.
• Small amt of untreated bitter flesh
characteristic of green olives
• 1 drop of phenolphthalein to cut
surface shows depth of lye
penetration
Post Lye Treatment
• Olives washed in cold H2O 24-36 hrs
• Water changed every 4 - 6 hrs
• Then response to indicator very faint
Fermentation
• Washed, lye-treated olives
transferred to 50 gal oak barrels
• Head replaced and hoops driven
• 11% brine added through side bung
– Lactic acid content 0.8 - 1.2%
– 3.8 pH or less
• Fermentation at 75 - 80oF for 1-12 mo
Producing Olive Oil
• Spain, Italy, and Greece (in that
order) produce 80% of world’s oil
• They consume 75%
• USA < 1% of world’s olive oil
• International Olive Oil Agreement
• Administered by International Olive
Oil Council in Madrid, Spain
Fatty Acid Profile
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Oil
Saturated
Unsaturated
Mono Poly
Olive 1st CP 3
88
9
Olive 2nd CP 11
83
5
Pecan C P
9
73
18
Cardin Pecan 5
85
10
Walnut EP
9
18
73
CP = Cold Pressed, EP= Expeller Pr
Definition of Olive Oil
• Olive oil - obtained solely from olives
• Excludes oil extracted by solvents or
reesterification processes, or any
mixtures with other oils
• Pure olive oil cannot be any olive
residue oils
Virgin Oil
• Mechanically pressed from olive fruit
without using heat - cold pressing
• Only washed, decantation, and
centrifugation (natural product)
• May have vintage years on label
Grades of Virgin Oil
• Virgin Olive Oil Extra
– Extra Vergine (Italian)
– Vierge Extra (French)
• Pure unadulterated oil from top
quality olives
• Perfect taste and odor
• Max of 1% acid and strong odors
Other Olive Oils
• Virgin Olive Oil Fine or Fino
– Almost perfect taste but 1.5% acid
• Semi-fine or Ordinary Olive Oil
– Good taste maximum acidity 3.3%
• Virgin Olive Oil Lampante > 3.3%
– Not for human consumption
Poorer Grades
• Refined oils
– Caustic soda used to purify virgin
oil from cull fruits
• Blended oil
– Blend of refined and virgin oil
– Most imported olive oil in USA
Residue Oil
• Olive-residue oil obtained by treating
pomace with solvents
THE END