Michigan apple maturity reports – September 28, 2011

Each week, MSU Extension educators test apples for maturity in their region and report the status.

This week’s regional reports:

Southwest Michigan – Bill Shane, Mark Longstroth, Diane Brown Michigan State University Extension

Southwest Michigan
Southwest Michigan

This is the fourth weekly apple maturity report for southwest Michigan. The samples for these reports are collected primarily in Berrien and Van Buren counties. The maturity is only a broad indication of trends for this area. Samples represent the more mature fruit in the blocks. Individual orchards may differ from these results.

Summary of Berrien County area apple maturity samples taken September 26, 2011

Variety Firmness lbs pressure (range) Starch (range) Brix degrees (range)
Empire 15.6 (12.9 - 17.5) 5.2 (3.2 - 7.6) 12.6 (11.4 - 13.4)
Jonagold 16.5 (15.4 - 17.3) 7.5 (7.0 - 8.0) 12.9 (11.4 - 14.3)
Jonathan 16.2 (16.0 - 16.6) 5.6 (2.0 - 7.6) 12.4 (10.8 - 13.3)
Golden Delicious 16.6 (15.8 - 17.3) 4.8 (3.6 - 6.4) 13.3 (11.9 - 14.7)
Red Delicious 16.9 (16.3 - 17.5) 3.5 (2.6 - 4.6) 10.8 ( 9.9 - 12.3)
Fuji 19.8 (17.7 - 21.9) 3.2 (2.4 - 4.0) 13.2 (11.3 - 14.8)
Idared 16.7 (16.1 - 17.2) 2.5 (2.2 - 3.0) 11.1 (10.6 - 11.6)

Empire (five sample sites). Firmness this week averages 15.6 lbs. (range 17.5 to 12.), about 1 pound less than last week, ranging from export to short-term controlled atmosphere (CA) firmness. The starch removal index average is 5.2 compared to 4.6 for last week, now with a wide range from immature to over-mature. The brix is averaging 12.6 compared to 12.0 for last week. The estimated peak harvest date for Empire destined for long term CA storage for the Benton Harbor region is September 21. Most Empires in the area destined for processing have been picked already. Due to the wide variability seen in these samples, growers will need to examine each block closely.

Jonagold (eight sample sites). This is the third week of sampling. Firmness is averaging 16.5 lbs. compared to 17.4 lbs. for last week, ranging from excellent to mid-term CA storage firmness. Starch conversion is now averaging 7.5, all in the over-mature range. Brix is still averaging 13.0 degrees. This variety has matured rapidly over the past week. Use of Smartfresh is recommended for this variety if storage life is needed.

Jonathan (seven sample sites). Firmness this week is averaging 16.2 compared to 17.8 lbs. for last week. All sites sampled had firmness in the excellent range, perched on the mid-term storage threshold, with starch conversion averaging 5.6 compared to 4.2 for last week, most in the mature to over-mature range. Brix averages 12.4, about the same as last week. Most sites tested are suitable for harvest for the fresh market for mid- to long term CA storage. The estimated peak harvest date for Jonathan destined for long term CA storage for the Benton Harbor region is September 26.

Golden Delicious (seven sites). This is the third week of sampling. Skin background color is generally still green at all sites sampled, but shows signs of brightening. Firmness is averaging 16.6 lbs., ranging from the excellent to mid-term CA storage categories – about 1 lb. less than last week. The average current starch removal index is 4.8, quite a bit higher than last week’s average of 2.7, with brix average of 13.3 (slightly higher than last week). Harvest of Golden Delicious for the long term fresh market is justified with sites testing relatively firm, but with starch conversion in the mature or over-mature range. This variety appears to be moving rapidly.

As mentioned in last week’s report, the estimated peak harvest date for Golden Delicious destined for long-term CA storage for the Benton Harbor region is October 1, but it appears that maturity is proceeding ahead of the predicted date.

Red Delicious (nine sites). Fruit firmness in this first week of sampling is averaging 16.9 lbs. compared to 17.7 lbs. for last week (current range 17.5 to 16.3), all in the mid-term controlled atmosphere firmness category. Starch conversion is averaging 3.5 compared to 2.5 for last week, now all in the mature range. Brix is averaging 10.8, only slightly higher than last week.

Like Golden Delicious, this variety is ahead of the predicted peak harvest date of October 1 for the Benton Harbor region. Pre-harvest drop is a concern in some blocks. Watercore was detected in a very few apples.

Main season Fuji (six sites). These are the traditional, later-season Fuji strains. Firmness averaged 19.8 lbs. (range 17.1 to 21.9) in the excellent to long term CA firmness range. Starch removal for this week averaged 3.2 (range 2.4 to 4.0), with a brix average of 13.2 (range of 11.3 to 14.8). Some sites are testing suitable for long term CA storage.

Idared (five sites). Flesh firmness averages 16.7 lbs. (range 17.2 to 16.1), with starch removal averaging 2.5 and average brix of 11.1 degrees. Firmness is excellent, with starch test in the immature range. Harvest for CA storage and more immediate sales can be delayed based on these tests. Harvest of Idared for processing is underway in area orchards.

Contact MSU fruit educator Bill Shane at the Southwest Michigan Research and Extension Center at 269-944-1477 ext. 205 if you would like to have samples from your farm tested for maturity. See the MSU Extension News for Agriculture website for more information, including reports from other regions, and the MSU apple website for information about apple maturity and apples in general.

This report and project is made possible by the support of our sponsors, which include Valent Biosciences, Michigan Apple Committee, Michigan State Horticultural Society, MSU’s AgBioResearch and Michigan State University Extension. Southwest Michigan growers providing apples include Grandview Orchards, Mammoth Farms, Oak Hill, Bixby Orchards, Weber Farms, Meachum Farms, Kevin Winkel Farms, Weckwerth Farms, Willmeng Farms, and Czuba Farms.

Apple maturity trends for SW Michigan. Each dot is the average for an orchard based on a 10 apple sample.
Samples were taken in Berrien and Van Buren counties.
Click here to view larger image.

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Southeast Michigan – Bob Tritten and Debbie Clark, Michigan State University Extension

Southeast Michigan
Southeast Michigan

General comments

Apple harvest continues at a rapid pace across the region with only one day over the last week of picking being interrupted due to rain on Monday (September 26). In fact, the rain ended around noontime at most farms and many growers were able to get a half-day of picking in. Growers are currently harvesting Jonathon, Jonagold and a few blocks of Empire and Golden Delicious are now ready for harvest for fruit destined for long-term storage. There is no doubt about Golden Delicious being well-ahead of Red Delicious this year in terms of maturity. In fact, there may be a bit of a gap between Golden harvest and the next group of varieties, which includes Red Delicious, Crispin, Idared and Northern Spy.

This week I sampled 10 varieties of apples, starting with Jonathon and Jonagold and continuing all the way through Fuji. Apple varieties that I sampled for the first time this week included Crispin, Idared and Northern Spy.

It still appears apples are mature about three to six days earlier than the predicted harvest dates which were published this summer. We feel the fruit is maturing earlier primarily due to the heat of this year’s growing season. Please remember that the order of harvest of apple varieties is different this year than most.

Apple Maturity in East Michigan for apples harvested on September 26, 2011


% Fruits with Ethylene over0.2 ppm (Range) Color (Range) Firmness Lbs (Range) Starch (Range)

Brix %

Jonathon 95% (90-100%) 85% (81-88%) 15.5 lbs (15.0-15.9) 5.3 (4.8-5.8) 12.6%
Jonagold 25% (0-80%) 72% (62-92%) 15.8 lbs (15.3-16.6) 5.6 (4.6-6.7) 12.9%
Empire 28% (0-50%) 84% (81-87%) 15.0 lbs (13.4-17.3) 3.5 (2.6-4.7) 11.2%
Cortland 63% (20-90%) 79% (77-82%) 13.3 lbs (12.7-14.3) 3.1 (2.6-3.5) 11.8%
Golden Delicious 32% (0-90%) 40% (approx.) 15.8 lbs (14.8-17.8) 4.1 (3.9-4.3) 12.8%
Red Delicious 40% (10-70%) 93% (89-95%) 15.2 lbs (14.4-17.1) 2.3 (2.0-2.5) 10.3%
Crispin 3% (0-60%) 38% (36-39%) 17.9 lbs (17.6-18.2) 1.8 (1.4-2.1) 12.6%
Idared 45% (20-70%) 76% (67-84%) 14.6 lbs (12.9-16.3) 1.8 (1.6-1.9) 11.0%
Northern Spy 83% (50-100%) 50% (27-62%) 19.3 lbs (18.0-20.4) 2.0 (1.6-2.6) 10.7%
Fuji 5% (0-10%) 63% (50-70%) 16.4 lbs (16.2-16.5) 2.3 (2.2-2.4) 11.9%

Individual variety results

Jonathon were sampled for the third week of the season. This will be the last week for sampling Jonathon, as most will be harvested. Most of the fruit (95 percent) are showing internal ethylene levels greater than 0.2 parts per million (ppm). The color has improved from 77 percent last week to 85 percent this week, and the pressure remains about the same at 15.5 lbs. The starch has jumped from 4.0 last week to 5.3 this week, with a range of starch indexes in tested blocks of 4.8 to 5.8. The brix has also improved to 12.6 percent, with the starch index of 5.3. Jonathon are ready for short-term storage and immediate fall sales, and some blocks are on the over-mature side for long-term storage.

Jonagold were sampled for the third week of the season as well. Most growers have started harvesting blocks of Jonagold depending on the strain. Jonagold are still not showing much internal ethylene development, with 25 percent of the fruit showing internal ethylene levels greater than 0.2 ppm. The color has improved dramatically on Jonagold to 72 percent over the last week; it was amazing for me to see the change in the four blocks tested from week to week.

I have not seen this much color on Jonagold for several years. The fruit have dropped over a pound of pressure, now at 15.8 lbs. The starch index has also jumped from 4.2 last week to 5.6 this week; however, there is a wide spread depending on strain and site from 4.6 to 6.7. The brix is tested at 12.9 percent. Jonagold are eating very good right now, with most right at their prime for fresh sales and intermediate storage. However, some blocks are over-mature for long-term and controlled atmosphere storage.

Empire were sampled for the third week of the season, with only 28 percent of fruit showing internal ethylene levels greater than 0.2 ppm. The color has improved to 84 percent and pressure has dropped from 16.3 lbs. last week to 15.0 lbs. this week. Starch removal has also started to climb, now averaging 3.5. However there is a wide range or a spread of starch readings from 2.6 to 4.7, with several of the blocks showing starch indexes in the 4.0 to 4.7 range. These blocks are ready for harvest for long-term and controlled atmosphere storage, while other blocks are still a bit green or immature.

For the most part, Empire for fresh market sales needs another few days to mature. Empire are picking very easy right now, however there has not been any considerable amount of drop as of yet.

Cortland were also sampled for the third week of the season. Cortland have had a lot of drop over the last week, however most of the drop was caused by “push-off” and not from weakness in the abscission layer. Color is about the same at 79 percent. The pressure has dropped dramatically from 16.0 lbs. last week to 13.1 lbs. this week. Oddly enough, the starch index is still testing a bit immature for all of the blocks of Cortland tested, now at 3.1. The brix has improved to 11.8 percent. Cortland are just a few days off from being mature.

Golden Delicious were sampled for the third week of the season, with Smoothee being the strain that I most often sample. The blush on Golden Delicious has improved greatly this past week. The pressure has dropped a pound to 15.8 lbs. and the starch removal index has moved from 3.2 last week to 4.1 this week. The brix has remained unchanged at 12.8 percent. Several blocks of Golden Delicious are ready now for long-term and controlled atmosphere storage, and for fresh market sales I would estimate that fruit need another three to four days to develop a bit more flavor.

Red Delicious were sampled for the second week of the season, with a more extensive sample taken this week than last week. Red Chief is the strain tested in all cases. Forty percent of the fruit are showing internal ethylene levels greater than 0.2 ppm – the color is still excellent at 93 percent. The fruit firmness has dropped a full two pounds to 15.2 lbs. this week. The starch removal index has not moved much over the last week and is now averaging 2.3 with very little spread of maturity. The brix is currently testing at 10.3 percent. Red Delicious are not mature in any blocks tested. I would estimate that they need another week to 10 days to mature – look for more details in next week’s report.

Crispin were sampled for the first time of the season. Very little of the fruit is showing internal ethylene levels greater than 0.2 ppm. The fruit color is looking better over the last week, with 38 percent of the fruit showing a blush. This is an extremely high number for Crispin, as it is rare to see so much color on Crispin. The fruit is still testing very firm at 17.9 lbs., with a starch index of 1.8 and a brix of 12.6 percent. I estimate that Crispin are most likely two weeks away from being ready for harvest.

Idared were sampled for the first week of the season, with 45 percent of the fruit showing internal ethylene levels greater than 0.2 ppm and the color is 76 percent. The fruit was surprisingly soft for the initial test with an average of 14.6 lbs. pressure, however there is a wide spread of pressures as low as 12.9 in one block and as high as 16.3 in another. There is not quite the same spread in the starch removal index and it now averages at 1.8. This fruit tested at 11 percent brix. Idared are immature at this time and need at least two weeks if not a little bit longer before they may be ready for long-term and controlled atmosphere storage harvest.

Northern Spy were sampled for the first time of the season with 83 percent of the fruit showing internal ethylene levels greater than 0.2 ppm. Color is very good on Northern Spys this year; it now stands at 50 percent. The color has improved greatly over the last week. The background color is still green at 2.8 and the fruit is very firm at 19.3 lbs. The starch removal index tested at 2.0 with a brix of 10.7 percent. Northern Spy’s are most likely about 10 days away from being ready for harvest for long term storage, but you can look for more details in next week’s report.

Fuji were sampled for the second time this season with very little fruit (5 percent) showing internal ethylene levels greater than 0.2 ppm. The fruit is still well colored at 63 percent and the fruit is still firm at 16.4 lbs. Starch removal index tested at 2.3 and brix of 11.9 percent. Fuji appears to be about 10 to 14 days away from beginning of harvest, but I would like to look at another week’s data to determine this for certain.

Predicted harvest dates

Full bloom date Original Predicted Harvest Dates Revised Predicted Harvest Dates
Station McIntosh Jons Reds McIntosh Jons Reds McIntosh Jons Reds
Deerfield 5/13 5/15 5/17 9/15 9/29 10/5 9/20 10/4 10/10
Romeo 5/19 5/21 5/21 9/17 10/2 10/8 9/22 10/7 10/13

If you have any questions regarding this apple maturity report or apple harvest in southeast Michigan, don’t hesitate to email me, call my office (810-244-8555) or cell (810-516-3800).

This report and project is made possible by the support of our sponsors, which include Valent Biosciences, Michigan Apple Committee, Michigan State Horticultural Society, MSU’s AgBioResearch and Michigan State University Extension. Southeast Michigan apple growers that are providing apples on a weekly basis include Spicer Orchards in Hartland, Erwin Orchards in South Lyon, Westview Orchards in Romeo and Hy’s Cider Mill in Romeo. Many thanks to the support of these growers.

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Northwest Michigan – Nikki Rothwell and Karen Powers, Michigan State University Extension

Northwest Michigan
Northwest Michigan

General comments

The Northwest Michigan Horticultural Research Station (NWMHRS) will be testing apples for maturity for 2011. If growers are interested in having fruit tested, they should drop off a 10 to 12 apple sample at the NWMHRS on Mondays. Fruit should be picked randomly from the outside portion of the trees and should be large in size and free of blemishes with the stem attached.

We tested five varieties this week and the fruit has moved along compared to last week’s samples. Brix has gone up in most varieties, despite the rain across the region. Firmness of all varieties is still good, and even McIntosh is still in the 15 lb. range. Growers are moving into Gala harvest and Galas are coming off in the more southerly regions and starting further north. McIntosh are also coming off this week and they are eating well at this time. We did see Macs falling from the tree due to the wind this past Monday (September 26).

Honeycrisp spot picking has started, particularly for those growers sending fruit to the fresh market. Growers feel fortunate as the past two Mondays have started out rainy, but rain has cleared out later in the day and allowed growers to get into the orchards post-rainfall.

Summary of northwest Michigan apple maturity samples taken on September 27, 2011

Variety Color % (range) Firmness lbs. pressure (range) Starch (range) Brix (range)
Gala (4) 87 (86.5-87) 18.2 (17.4-19) 2.4 11.7 (10.7-12.6)
McIntosh (5) 92 15.1 (14.2-15.7) 4.4 (1.4-6.7) 11.5 (10.7-13)
Honeycrisp (5) 79 (71.5-86) 15.5 (14.5-17.2) 5.5 (3.6-7.2) 12.5 (11.3-15.5)
Golden Delicious (2) 23 16.8 2.4 12.1
Jonagold (3) 87 (77-94) 18.4 (17.7-18.8) 3.4 (2.9-4.5) 13.3 (12.8-13.7)

Gala. Approaching mature (four samples). Gala harvest has started across the region. Firmness of Galas still has not changed in the past week, and most samples still have firmnesses in the 19 lb. pressure range; this information is similar to last week’s report. Starch index levels also remain constant and are in the 2.5 range, and start removal was consistent across the different blocks tested. Color on Galas looks pretty good.

McIntosh. Mature (five samples). Fruit firmness has dropped over the last week, but is still in the 15 lb. range, and growers are starting to pick Macs across the region. Starch index has increased in the past week, but from the samples tested, there is quite a spread in the starch readings: 1.4 to 6.7. Brix has also increased to an average of 11.5. Color on Macs is good at 92 percent.

Honeycrisp. Mature (four samples). Firmness in Honeycrisp is pretty consistent across the four samples, and the average firmness is in the 15.5 lb. range. Again this week there is quite a bit of variability in the starch removal index where the numbers range from 3.6 to 7.2. Color has remained consistent from last week and the average is 79 percent. Growers have started spot picking this variety.

Golden Delicious. Immature (two samples). Golden Delicious firmness has dropped a pound or so from last week and the average firmness is 16.8 lbs. Starch removal is an average of 2.4 this week, which is slightly higher than last week. Color of Goldens at this time is 23 percent.

Jonagold. Immature (three samples). Jonagolds are firm and the average is 18.4 lbs, and from the samples we took this week, they are fairly consistent. Starch removal has increased this week, with an average of 3.4. Brix has also increased in the last week, and color is looking good at an average of 83 percent.

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Grand Rapids Area
Grand Rapids Area

Grand Rapids Area – Phil Schwallier, Amy Irish-Brown, Denise Ruwersma, Michigan State University Extension

General comments

Cooler temperatures and some sunshine have continued to help color apples. The Great Lakes area has been stuck under an upper level low since the end of last week. This has brought on-again, off-again rain to the whole state for the last week of weather. Some areas have had significant rainfall totals and other areas have had very little. Growers continue to report picking out just about what they expected or slightly above. Some growers are starting to feel a little pinch from not enough labor for harvest. No one is reporting having to turn workers away.

Summary of Grand Rapids apple maturity samples tested September 27, 2011

Variety Predicted Harvest Date Avg. Ethylene (ppm) % Fruits with Ethylene over 0.2 ppm % Red Color (range) Firmness lbs pressure (range) Starch (range) Brix (range)
Cortland 25-Sep 0.55 70% 95% 16.7 (14.6-19.8 2.2 (2-4) 12.4 (12-13)
Jonagold 30-Sep 0.19 15% 58% (30-80) 17.4 (14.9-20.5) 6.8 (5-8) 11.5 (10-13.5)
Golden Delicious 4-Oct 0.062 0% 4.5 (0-20) 16.1 (13.9-19.8) 5 (3-7) 11 (9.8-13.2)
Red Delicious 6-Oct 0.31 30% 94% (85-100) 17.3 (14.4-19.3) 2.3 (2-4) 9.9 (9-12)
Cameo 8-Oct? 0.122 10% 84.5% (70-95) 17.6 (16.4-19.1) 3 11
Nova Spy 8-Oct? 1.1 90% 75% (65-90) 19.2 (17-20.6) 5.2 (5-6) 12.6 (12-13.5)
Northern Spy 10-Oct 0.158 10% 7.5 (0-30) 19.6 (17.8-20.5) 2.4 (2-3) 9.2 (8.8-9.5)
Mutsu 12-Oct 0.0597 0% 2.5% (0-10) 18.7 (15.6-20.5) 2 9.5 (8.8-10.2)
Idared 12-Oct 0.133 0% 52.5 (35-70) 16.3 (13.6-19.1) 2.1 (2-3) 9.4 (8-10.8)
Law Rome 17-Oct 0.034 0% 97.5 (80-100) 20.5 (20.3-21.1) 3 10.5 (10-11)
Fuji 27-Oct 1.65 90% 73% (35-95) 17 (11.8-20.7) 4 (2-6) 13 (11.6-17)


There are a few Galas still hanging, but most growers are finishing up with this variety. Non-Retain treated fruit are in a short-term CA window or for direct fall sales only at this time.


Most Honeycrisp harvest is complete. There are a few blocks with some rather green fruit still hanging, but those will be finished up by the end of the week.


Empire harvest is just beginning on the Ridge. Fruit tested late last week were showing to be at an optimum window for long-term storage for this week. Empire eats much better this week than last.


Inlast week’s report, the wrong predicted harvest date was listed for Cortland. This variety is usually harvested around the same time as Jonathan or September 24-25, 2011. There have been some Cortlands harvested and ready for long-term storage. Starch clearing is low, but other readings indicate they are just moving into the harvest window. There is some fruit drop in Cortland, most likely due to the fruits pushing themselves off rather than from an over-maturity issue.


Harvest for Jonathan is just beginning and fruits are conditioned for long-term CA storage on the Ridge this week. The next two weeks will be big for Jonathan harvest around Grand Rapids. There is some bleeding of red color into the flesh, especially in Ruby Jon and it’s just beginning to start in Jonee. The predicted harvest date for Jonathan in general is September 29.


Jonagold is just moving into a window for long-term CA storage. The maturity indicators have not moved too much from last week to this week and they don’t eat quite right just yet. Internal ethylene is still quite low at 0.19 with only 15 percent of fruits being over the climacteric of 0.2 ppm – that’s surprisingly only up slightly from last week’s samples and still indicates immaturity. Firmness is still excellent at an average of 17.4 pounds. Starch clearing is at 6.8, up from 5.5 last week. Brix are only slightly improved from 11.3 last week to 11.5 on average for this week. Color development has greatly improved in Jonagold even in the last couple of days. If color is good, some initial Jonagold harvest can begin. The predicted harvest date in the Grand Rapids area for Jonagold is September 30.

Golden Delicious

The predicted harvest date is October 2 for Goldens. There is some early harvest occurring just in the last day or two. Firmness is excellent and the starch clearing is averaging 5. Brix are at 11 and could use a little improvement. The long-term CA window is just opening for Golden Delicious.

Red Delicious

All samples still indicate immature fruits, but it appears that Red Delicious is going to mature ahead of predicted harvest dates for 2011. The predicted date is October 6 and some fruits will be ready for long-term storage just ahead of that date. Growers should keep an eye on their Reds, especially those blocks that they know can be ahead of other areas. Data from sampled fruits indicate immaturity: only 30 percent of fruits are showing ethylene over 0.2 ppm; fruit are very hard at 17.3 pounds; starch clearing is only 2.3; and brix is very low at only 9.9 on average.


Cameo is a new variety and was sampled for the first time this week. All numbers indicate immaturity. The predicted harvest window for Cameo on the Ridge looks to be around October 8, but since this variety is fairly new, we will learn as we go. It looks like it will mature right after Red Delicious, perhaps with Ida Red.

Nova Spy and Northern Spy

Nova Spy is also fairly new to the Ridge area and thought to mature a few days ahead of Northern Spy. The numbers from our samples show this to be true. Last week, Nova Spy was still immature, but readings this week show a great improvement in fruit quality and fruits are ready for long-term storage at this time. Perhaps the predicted harvest date of October 8 is a little late. Northern Spy sampled this week are immature, but by next week, should make that leap forward to being closer to the long-term storage window.


Mutsu were sampled for the first time this week and are immature.

Ida Red

Ida Reds were sampled for the first time this week and are immature, but readings are a little surprising for this early in the harvest season. Perhaps Ida Red will be ahead of the predicted harvest date of October 12.

Law Rome

Fruit are immature, but like Ida Red, readings are surprisingly ahead of what is expected. The predicted harvest date for Rome in general is October 17 and Law Rome is usually slightly ahead of regular Romes.

Fuji (late season)

Late season Fuji was tested for the first time this week and all signs indicate immaturity. The predicted harvest date for Fuji in Grand Rapids is October 27 and like other varieties this year, this date might be a bit on the late side. Another week of sampling will give a good idea of how Fuji is maturing.

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