By Jamie Slingerland
Vintages are shaped by the weather and in 2024 a strong El Nino shaped the vintage. 2024 went down as the warmest year in recorded history in Niagara as well as Canada and the world but in Niagara we did not experience a lot of +30 C temperatures, which El Ninos have brought in the past.
Editor’s Note: Jamie Slingerland (below) is the director of viniculture for Pillitteri Estates Winery. He has contributed to Wines in Niagara’s annual Harvest Report for many years. We value his thoughts and have decided to publish it separately from the main report, which was published March 5, here.
It should be noted that 2024 was a large crop with fruit bud survival high but vines tend to crop lighter the following year. In most varieties in 2024 that was prevalent. The warm fall, particularly at night, contributed to skin break, insect activity and disease pressure.
Location, location, location!
The best location to grow grapes in Ontario is in Niagara-on-the-Lake where 65-70% of Ontario’s grapes, 95% of the Bordeaux varieties, about 80% of the entire red vinifera crop and 95% of the icewine is produced. The combined reasons are this: vines survive winter better due to a greater lake effect, less risk of spring frost, greater growing degree days, as for icewine there are larger grape growing operations located in NOTL that have capacity to harvest and press icewine grapes. With 99.9% of the icewine grape harvest being mechanized, a polar vortex can bring 3-4 days/nights of sufficient cold (ideal is -10 C to -12 C) to harvest most of the icewine grape crop.
Winter: December, January and February
2023-24 was mild again like last winter
Winter for a vintage is December, January and February. It was a warm winter with few freezing days and almost no ground frost. The ground was bare of snow almost the entire winter. If you were a skier, you missed out this winter. This proved difficult for icewine grapes, as they turned brown later, in January, just as the cold snap took place. Icewine is always a risk, but it seemed like winter would not come until a short cold snap mid-January 2024. Since there was no severe cold in the winter, vine/bud survival was excellent. The vines went into winter with good wood and were in good shape.
December 2023 was warmer with only nine nights below freezing and essentially zero precipitation. Vines went into the fall great with the warm weather, but that warm weather did not make the icewine grapes turn brown and hastened dehydration.
All of January 2024 was mild with most days near 0 C. Precipitation was low at about 6 cm. Icewine grapes took longer to brown than previous years because it was still too warm. That browning due to cold weather creates those unique flavours. Icewine grapes in December and January dehydrated about 35% more than at the same time in previous years. With no snow cover, birds had plenty of food on the ground, so they were less ferocious in their attacks on the icewine grapes which usually makes up most Icewine grape losses. The exception to the mild weather all January was a beautiful cold week, if you were growing icewine grapes or a skier, from Jan. 14-20. Thanks to that moderate Polar Vortex the icewine crop was saved, the grapes turned brown and most of the icewine grapes were harvested. Icewine juice was of excellent quality.
February continued to be much warmer than the historical average as well with almost zero precipitation. Most people wondered, where had winter gone?
Growers’ wind machines, that are used to combat cold inversions, sat silent all winter. A relief to the wallet, sleepless nights for growers and the neighbours too, lol.
Spring: March, April,
May 2024 was dry and warm
With the fear of most cold weather gone, most growers watched to see if there would be a spring cold snap or if buds pushed too early. It looked for sure that spring bud break would be a few weeks earlier. Spring frost for most grapes in Niagara is not normally a concern. Fruit bud survival at this point was close to 90%. A 60% fruit bud survival rate can achieve a full crop with good vineyard management. Growers always leave extra buds to account for fruit bud loss on most varieties because “you can always remove excess fruit, but you can’t add fruit to a vine when there is a light crop.” Too light of a crop can reduce grape quality for wine because vines need to be in balance with crop load so that vegetative growth does not become excessive and reduce sun exposure and air flow to the fruit that would reduce fruit quality.
March followed the winter trend of warm and dry with less than 2.5 cm of rain and no snow fall. There were only six nights below freezing with the coldest at -5 C and almost every day was above freezing. El Nino was holding strong with no end in sight.
April was near normal for rainfall with about 7.5 cm, mostly at two periods. This helped rebuild soil moisture reserves as there was no snow cover melt. Every day was above freezing with unusually warm weather for another month. Buds were still dormant but deacclimation was advanced meaning fruit buds would be susceptible if a hard cold snap happened, but it didn’t occur.
May had mild weather as well as warm nights. In NOTL everyone used to say once you are past the Victoria Day weekend you were free of frost but in the last 20 years it seems that date has moved up to May 10. In 2024, the last day of frost was mid-April. Essentially, we were free of frost for almost two months. Although most areas had great bud survival but there were some cold pockets that somehow had bud damage, so a few fields and a few varieties had lower bud survival. That’s when and where wind machines come in handy for those anomalies.
May had 10 days with rain but nothing more than 1 cm at a time and mostly during the last week of the month. Moisture reserves in the soil were about 40% below normal. Bud burst was 7-10 days ahead of historical and cultivation was in full swing in early May.
Summer: June, July, August 2023
was warmer nights, sufficient moisture
It’s best to describe the 2024 summer as one of the best patio summers in years both day and night. No extreme hot days but nights were warm. From the vines’ perspective they grew well with the heat and there was enough precipitation for the vines to do well so irrigation was not needed. Lots of moisture and heat creates green growth. Growers open up the canopy through the summer with leaf pull and hedging for improved insect/disease control and improve ripening.
In the summer of 2024 growers did a lot more hedging, and leaf pulling than previous years. Disease and insect pressure built up all summer due to warm night and lots of moisture. But on the bright side, irrigation was not needed nor did vineyards stress or leaves wilt to the heat. At about 28 C the vines begin to close their stomata and at greater temperatures like 40 C the stomata completely closes causing the wilting of the grape leaves.
In 2024 there was no wilting, and the stomata did not even partially close as almost every day was below 30 C. What had become apparent to growers was that there were going to be more grapes than what wineries could purchase. Years of tough market conditions and low margins had wineries with hefty inventories so there was an evolving situation of more grapes than the wineries needed. Uncontracted grapes were the first to fill up the unsold grape list and it was one of the biggest lists ever seen.
June weather was warmer than historical with mostly mid-20s in the day and 4-5 days of 30 C. Rainfall was also above historical. There were nine days of small amounts of rain and 3-4 days that were heavy, accumulating up to 11 cm for the month. A quick 4.5 cm rainfall caused flooding which slowed field operations for a few days. Grape vine growth rocketed with the warm June weather, early (May) season cultivation, and lots of rain that replenished soil reserves. That push in growth led to bloom a week earlier. Generally, this is the kind of weather that is needed to help push the late maturing varieties to full mature in the fall, varieties like the Cabs. This was a promising sign of a great Bordeaux grape varietal vintage in Niagara. But that warmer than usual nights in June also increased disease and insect pressure.
July typically is the hottest month of summer. Surprisingly, July during this El Nino had moderate but warm days with only 2-3 days reaching 30 C. Nights were generally consistently warm but not hot. Grape vines love heat, so the 25-30 C was good as was the higher-than-average 12 cm of rain. That weather was also good for a consistent growth pattern of disease and insects. There was a quick heavy soaker of 6.5 cm rain in one day mid-July which maintained soil moisture levels reducing the need for irrigation. That rainfall also caused ditches to overflow and fields to be flooded. All equipment activity in fields was halted for almost a week creating an opening for disease and insects to rapidly reproduce. Things still looked very good in the field but we knew we had a lot of disease and insect control to stay on top of. Fruit removal was heavy in only a few varieties or fields but generally there was little excess fruit to remove other than secondaries.
August had almost the same temperatures as July, fairly warm at night and close to but below 30 C most days. Whereas there was only 6.5 cm of rain. Soil reserves of moisture were more than sufficient for continued vine growth, so no one needed to irrigate. In August, just when you had thought you finished leaf pulling, you had to go back at it again. There was also a lot of hedging as well. Growers in August were continuously opening up the canopy for disease/insect control, to advance veraison and for secondary fruit removal. Signs of downy mildew seemed to be a constant battle as was insect activity. The crop by the end of August looked to be a bit lighter than 2023 by about 9-10%. As far as crops go it was still a good-sized crop. Grape quality was also promising.
Fall: September, October, November 2024
Fall 2024 had lower than average rainfall and it seemed like summer wouldn’t end with warm days and with every night warmer than average. Pool and patio season looked be extending into the fall in 2024. But for grapes, growers want cool weather to reduce disease/insect pressure and stop grape skins from thinning as well cooler nights help preserve acidity and aromas as grapes ripen.
The warm fall 2024 became a battle of fighting disease, insects and thin grape skins. Downy mildew (DM) was throughout all vineyards on foliage. Light amounts of DM can have little effect upon fruit quality but in high amounts photosynthesis is affected and fruit quality/ripening is diminished. For organic grape growers this was disastrous as most products used to combat pretty well all diseases are suppressive and not eradicates. I witnessed one organic vineyard in the fall of 2024 without 90% of their leaves and little crop. I am watching it to see if the vineyard is alive in 2025. Organically grown grapes do extremely well in dry desert like conditions where humidity levels are at near 0%. That doesn’t happen in Ontario. This fall separated the men from the boys and the lucky and unlucky.
There was some great quality, but it was a challenge to keep fields clean. This wasn’t a fall where you could hold harvest off for a few weeks on mid-season varieties to advantage grape of desiccation or to intensify brix and flavours.
Timing, grower skill set, and luck was critical. With that being said, I was impressed with grape quality for wine. In spite of the challenges of the grape harvest quality ended up variable with mostly excellent and good quality and in some cases not so good. Those warm conditions were mostly a blessing and a curse at times. We growers and winemakers are so picky sometimes always looking for perfection when nature is far from perfect.
So, 2024 will be remembered for both reserve wines and entry level quaffable wines in 2024, lol. A symptom of the challenging weather in 2024 was the reduced appassimento harvest with our winery only producing 10 tonnes of Cabernet Sauvignon for appassimento. This is ¼ of last year’s appassimento harvest and with four less varieties. We could not trust those other varieties to dry over 30 days with thin skins from warm weather.
September 2024 started off with a long list of surplus grapes without buyers. As for the weather it was warmer than the historical average. It was a continuation of good weather from July and August but was 5 C cooler in the mid-20s in the day and mid-teens at night. Rainfall was less in September than August, which is usually the opposite.
Most growers speculated that the crop was not bigger than 2023 yet estimating is always an imperfect science as moisture levels can change a crop easily by 5-10% either way. Moisture levels were never short through the growing season so many of us though it would be close to 2023. As harvest began, tonnages came in a bit lighter. Disease and insect damage began to chisel a bit of the tonnage down on the tight bunched varieties that are predominant in September.
Pinot Gris proved to be an amazing exception for us with volumes that were slightly above that of 2023 and with the best quality that I have ever harvested. I was pretty nervous when everyone asked if I could hang the grapes longer; I did, and it was a fantastic Pinot Gris crop! Grapes without buyers did not hang long on the vine if they were 1-2 weeks past their optimum picking date, which accounted for much of the lost grapes.
October 2024 started to change for crop demand as wineries realized fields were coming up short. Uncontracted grapes began to sell and by the end of the month the surplus was gone. The weather had untraditionally dry weather, imagine, less rainfall than August. Also, two-thirds of the month was near 20 C. Nights and days on the patio had never been better for October. But disease/insect pressure wouldn’t stop. Field loss on tight bunch varieties began to mount. There was even some breakdown on looser Bordeaux variety bunches. A few fields left on the vine longer were lost and others were picked just in time. Downy mildew was visible in almost all vineyards on the leaves. The warm weather in later September and October caused skins on many varieties to have some breakdown (slip skin). The better growers out there were able to clean it up and only experience a 5-10% loss, but others fared worse.
The surplus of grapes had basically disappeared mostly to lower than harvested yields per variety. Those lower yields were due to a shorter crop and losses due to warm fall weather. Wineries basically bought whatever was still good on the vine. After harvest growers on Vinifera grapes mostly hill up the vines to protect the graft between the rootstock and fruit wood.
This extra work in the fall protects the vine in extreme winters when everything above the hill is killed resulting in a zero crop. This is a rare occurrence which only happened twice in the last 40+ years but allows growers to renew their vineyards so that they can get a crop the following year and so they do not need to replant the Vineyard.
The first two weeks of November 2024 continued with much warmer temperatures than normal. There were three days above 20 C and only as much rain as August. Many growers looking to leave grapes for icewine, like our winery, were clenching their teeth waiting for the cold to drop the leaves so the nets could be tied. Mother Nature came to the rescue in the last two weeks, and it seemed that normal late November weather had arrived. Maybe La Nina was starting? Temperatures in the last two weeks of November averaged around 10 C with nights near a few 5 C.
With these cooler temperatures and shorter days, the leaf begins to drain itself of chlorophyll and a change in the levels of the hormone auxin occurs which weakens the bond between the leaf and cane. A good frost usually causes the leaf to dry up and the wind eventually blows off the leaves. There was a good rainfall towards the end of November and that hastened the leaf drop so that icewine nets could be tied. If dried leaves are left in the net the leaves act as an insulation and grapes won’t turn brown from freezing temperatures which is required to develop icewine flavours. Tying the net for icewine is not the easiest job and we luckily finished by the start of December.
December 2024 turned out to be
good weather for icewine
There were 11 days below 0 C helping grapes turn brown. The colder weather was the beginning of the long predicted, but mild, La Nina. It was a surprising cooler change from December 2023. Grapes turned brown with freezing temperatures, and we were able to harvest four days before Christmas. 15-30 years ago, we harvested icewine grapes once before Christmas, once before New Year’s then the rest the first few weeks in January. We haven’t had the right conditions to do that for the last 15 years. What was a real pleasure was we harvested our “Amarone” Vineyard” (Corvina, Rondinella and Molinar grape varieties) — the first time we picked it for icewine. Yes, this is the only commercial vineyard of this variety in Canada.
First planted in 2010 and 2011, these 4,000 vines were green-shoot grafted in a greenhouse from a handful of cuttings and resulted in The Premier’s Award for Agri-Food Innovation Excellence in 2011 for Pillitteri Estates Winery. Led by researcher Helen Fisher and thanks to a collaboration of University of Guelph, UC Davis, OMAFRA, VRIC, CCOVI and Vinetech, 80 fruit buds in three months, two times produced a lot of vines. After many appassimento years with these grapes we produced from the first ever icewine from the 2024 crop.
In December 2024 we produced 3,000L of the first in the world Corvina icewine. As for the Vidal grapes, those were harvested in January 2025 and resulted in some exceptional qualities and quantities for our winery. Overall, the 2024 Icewine crop was half of 2023. In my opinion this was because surplus grapes from 2023 Vintage created strong inventories and that the 2024 vintage in the end had no surplus grapes left to harvest for icewine. Overall tonnage for icewine grapes fell from approximately 4,000 tonnes in 2023 to approximately 1,600 tonnes in 2024, a 60% drop in grapes left for icewine.
I have harvested icewine grapes for 36 years. First in 1988 with my brother-in-law Charlie and father-in-law Gary, as amateur winemakers, we hand-picked grapes on our knees emptying the nets into grape boxes then into hand operated basket presses. Starting in 1993 when the winery opened, we had larger hand-picking crews that over the years grew to 30-60 people a night, 8-10 nights a season but only picking 10 to 20 tonnes a night. Difficulty in finding enough workers to pick icewine back then necessitated machine harvesting some 20 years ago and we, like other growers, now machine harvest over long hours and on two nights in January 2025 we picked 200 tonnes in 20 hours.
According to the GGO annual report, the overall crop in 2024 was 64,826 tonnes down from 75,727 tonnes in 2023, a 15% decline in production from a big crop year.
All varieties were in decline from 2023 except: Cabernet Franc up 233 tonnes, Pinot Gris up 55 tonnes, Gamay up 27 tonnes, experimental whites up 19 tonnes, Cab Sauv up 14 tonnes, and experimental reds up 13 tonnes. Red vinifera had the lowest decline at 161 tonnes. White vinifera was down 1,558 tonnes, red hybrids were down 1,550, white hybrids were down 3,744 tonnes.
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