Grand Rapids area apple maturity report – Oct. 13, 2021

This is the 10th and final apple maturity report for the Grand Rapids, Michigan, region.

Red apples hanging from a tree.
Fuji apples showing much improved red color development in Sparta, Michigan, on Monday, Oct. 11, 2021. Photo by Anna Wallis, MSU Extension.

This is the 10th and final apple maturity report for the 2021 harvest season. Reports are sent out every week (usually on Wednesdays), following the Michigan State University Extension fruit team apple maturity calls on Wednesday morning.

For general information about how samples are collected and processed, please refer to Apple Maturity Report #1.

How to read the maturity tables

For each variety evaluated, we provide data from our evaluations in a table. In each, a row is provided for each sample tested. This allows you to see how the varieties may be progressing in different regions or specific locations. An average is included for each variety. Maximum and minimum values are included for the highest and lowest individual fruits evaluated for each, to give a full spectrum of the maturity. Recommended values are included for each variety at the bottom of the table. These suggested values for firmness and starch index were also published in a standalone table format. Firmness ranges encompass long and short-term storage recommendations.

Updates for this week

This will be the last report of the season. Harvest is wrapping up quickly and many of our sample locations were harvested at the time of collection for this report.

Conditions have continued to be warmer than normal over the past week, with highs in the 70s degrees Fahrenheit and lows mostly remaining in the 50-60s. This is less than ideal for red color development. In addition, we have had a considerable amount of rain and wind in the past week. Approximately 0.5 inches of accumulation was recorded Friday evening into Saturday in Sparta, Michigan, and an additional 0.65 inches Sunday through Tuesday. Heavy wind knocked leaves and, in some cases, a little fruit off of trees.

There is considerable variability in maturity and quality for many varieties due to the extended bloom, warm season and ample rainfall this season. Overall, fruit is softer and more mature this year than it has been in the previous two years. As a result, fruit going into bins may be a wide range of quality, which will have important impacts on storage. It will be critical to do everything possible to ensure optimum storage conditions. This includes cooling fruit quickly, and treatment with 1-MCP.

Red Delicious is continuing harvest this week in most locations.

Fuji is showing signs of maturity and harvesting this week in most locations.

Evercrisp is showing signs of maturity and should begin harvest this week or next week.

Rome and Braeburn are also showing signs of maturity and picking in most locations.

Red Delicious

This variety is continuing to be harvested in many locations this week. Only one sample was collected for testing this week and other sample locations have been harvested. Ethylene development is evident in many samples with some over the 0.2 ppm climacteric. Pressures have decreased this week. Typically, we like to see pressure of about 15 pounds at the consumer end, and fruit harvested at this pressure are beyond the appropriate condition for long term controlled atmosphere (CA) storage. Model predicted harvest was Oct. 7 for this variety.

Red Delicious sampled Oct. 11

Variety

Location

Fruit Weight (g)

Ethylene (% >0.2ppm)

Red Color (%)

Background color (5-1)

Firmness (lbs)

Starch (1-7)

Soluble Solids (°Brix)

Red Delicious

Ridge4

181

100%

92.0

1.0

14.6

4.4

13.5

Average

 

181

100%

92.0

1.0

14.6

4.4

13.5

Max

 

 

 

80.0

1.0

13.0

3.0

 

Min

 

 

 

100.0

1.0

15.5

6.0

 

Recommended

 

 

 

 

 

16-18

2.5-6

 

Red Delicious weekly averages

Collection Date

Fruit Weight (g)

Ethylene (% Fruit >0.2ppm)

Red Color (%)

Background color (5-1)

Firmness (lbs)

Starch (1-6)

Soluble Solids (°Brix)

13-Sep

190

40%

89.0 (75-100)

2.2 (3-1)

18.1 (16.0-21.0)

2.3 (2-3)

11.5 (10.9-12.0)

20-Sep

190

30%

   

17.0 (15.0-20.0)

2.7 (2-5)

12.5 (11.0-14.5)

27-Sep

200

47%

84.6 (60-100)

1.2 (2-1)

16.0 (14.0-19.0)

3.6 (2-7)

13.2 (14.0-14.0)

4-Oct

215

80%

89.8 (65-100)

1.0 (2-1)

15.6 (13.0-17.8)

4.3 (3-7)

13.5 (12.6-13.9)

11-Oct

181

100%

92.0 (80-100)

1.0 (1-1)

14.6 (13.0-15.5)

4.4 (3-6)

13.5

Rome

Overall, Rome is mature or nearly mature and picking in most places. Firmness decreased a bit again this week, but still needs a bit more time in this particular block. In other locations, apples are ready to harvest. Sugars and starch did not change much from last week but are close to the appropriate range for harvest. Model predicted harvest was Oct. 14, and we anticipate it to be close to accurate but like everything else this season, they might come in slightly earlier. There was no color bleeding in any of the Romes we sampled.

Rome sampled Oct. 11

Variety

Location

Fruit Weight (g)

Ethylene (% >0.2ppm)

Red Color (%)

Background color (5-1)

Firmness (lbs)

Starch (1-7)

Soluble Solids (°Brix)

Rome

Ridge3

172

0%

88.0

2.0

19.9

3.5

12.7

Average

 

172

0%

88.0

2.0

19.9

3.5

12.7

Max

 

 

 

75.0

2.0

19.0

3.0

 

Min

 

 

 

95.0

2.0

21.7

5.0

 

Recommended

 

 

 

 

 

15-18

3-5.5

 

Rome weekly averages

Collection Date

Fruit Weight (g)

Ethylene (% Fruit >0.2ppm)

Red Color (%)

Background color (5-1)

Firmness (lbs)

Starch (1-6)

Soluble Solids (°Brix)

20-Sep

180

0%

78.5 (60-90)

3 (3-3)

24.5 (23.0-27.0)

2.7 (2-3)

11.3

27-Sep

158

0%

86.4 (50-100)

2.9 (3-2)

24.1 (15.5-29.0)

2.8 (2-4)

11.8

4-Oct

183

0%

87.0 (75-100)

1.9 (3-1)

22.1 (19.5-26.0)

3.3 (3-4)

12.8

11-Oct

172

0%

88.0 (75-95)

2.0 (2-2)

19.9 (19.0-21.7)

3.5 (3-5)

12.7

Fuji

Fuji is nearly mature in most locations. Internal characteristics (starch, sugars and pressure) indicate fruit is mature. Color is much improved from last week but less than excellent. Water core was observed in a number of fruit this week but was relatively minor. This variety does not stain well with iodine, and starch pattern fades quickly. Internal ethylene is being produced in a nearly all fruit. Model-predicted harvest was Oct. 20 but we believe fruit is internally ready for harvest. A few more days may help to improve color.

Fuji sampled Oct. 11

Variety

Location

Fruit Weight (g)

Ethylene (% >0.2ppm)

Red Color (%)

Background color (5-1)

Firmness (lbs)

Starch (1-7)

Soluble Solids (°Brix)

Fuji

Belding1

250

100%

50.4

2.3

17.1

5.1

13.5

Fuji

Belding3

240

100%

85.0

2.0

19.2

4.4

15.1

Fuji

Ridge2

239

100%

83.5

2.0

14.3

6.3

15.7

Fuji

Ridge3

266

100%

92.5

1.2

17.1

6.6

17.0

Average

 

249

100%

77.9

1.9

16.9

5.6

15.3

Max

 

 

 

95.0

3.0

21.2

7.0

17.0

Min

 

 

 

4.0

1.0

13.0

4.0

13.5

Recommended

 

 

 

 

 

16-18

3-7

 

Fuji weekly averages

Collection Date

Fruit Weight (g)

Ethylene (% Fruit >0.2ppm)

Red Color (%)

Background color (5-1)

Firmness (lbs)

Starch (1-6)

Soluble Solids (°Brix)

20-Sep

205

55%

46.3 (5-80)

6.5 (4-3)

19.6 (14.5-23.2)

1.9 (1-4)

13.5 (11.4-15.5)

27-Sep

226

50%

71.3 (40-95)

2.8 (3-1)

18.5 (14.0-23.4)

3.6 (2-5)

14.0 (13.2-14.5)

4-Oct

233

85%

76.9 (40-100)

2.1 (3-1)

16.9 (14.8-21.0)

4.6 (1-7)

14.2 (12.8-15.8)

11-Oct

249

100%

77.9 (40-95)

1.9 (3-1)

16.9 (13.0-21.2)

5.6 (4-7)

15.3 (13.5-17.0)

Evercrisp

Overall, Evercrisp is still nearly mature. A little more red color development has taken place but more is necessary. Background color is still fairly green but improving. This is a high ethylene producing variety, which was detected in all samples. Pressure decreased a little this week but is still very high and starch is continuing to clear. Soluble solids are high, which is likely a contribution of the Fuji background. Water core was detected in several fruit in two samples this week.

Evercrisp sampled Oct. 11

Variety

Location

Fruit Weight (g)

Ethylene (% >0.2ppm)

Red Color (%)

Background color (5-1)

Firmness (lbs)

Starch (1-7)

Soluble Solids (°Brix)

Evercrisp

Belding1

239

100%

62.5

2.6

19.9

5.6

14.2

Evercrisp

Belding3

260

100%

58.5

2.8

22.7

2.2

14.5

Evercrisp

Ridge1

188

100%

71.0

2.2

18.7

6.5

17.1

Evercrisp

Ridge4

316

100%

55.0

2.4

23.7

5.9

17.2

Average

 

251

100%

61.8

2.5

21.2

5.0

15.8

Max

 

 

 

90.0

4.0

29.0

8.0

17.2

Min

 

 

 

25.0

2.0

16.0

2.0

14.2

Recommended

 

 

 

 

 

 

 

 

Evercrisp weekly averages

Collection Date

Fruit Weight (g)

Ethylene (% Fruit >0.2ppm)

Red Color (%)

Background color (5-1)

Firmness (lbs)

Starch (1-6)

Soluble Solids (°Brix)

20-Sep

233

73%

14.3 (10-40)

4 (4-4)

25.1 (20.5-31.1)

1.9 (1-4)

13.5 (11.4-15.5)

27-Sep

227

92%

50.4 (0-90)

3.7 (5-2)

23.9 (20.0-30.9)

2.8 (1-8)

14.5 (12.3-16.0)

4-Oct

234

90%

57.3 (10-90)

3.1 (4-2)

23.1 (17.0-28.0)

3.9 (2-7)

15.0 (12.9-16.0)

11-Oct

251

100%

61.8 (25-90)

2.5 (4-2)

21.2 (16.0-29.0)

5.0 (2-8)

15.8 (14.2-17.2)

Fuji watercore starch samples.
Fuji apples stained with iodine on Oct. 12 with considerable starch clearing. However, staining is light in this variety due to a different type of amylose present than other varieties. Many fruit also had symptoms of water core (water soaking in the vascular bundles). Water core typically begins in the shoulders of the fruit. Photo by Anna Wallis, MSU Extension.

Apple maturity sampling parameters

  • % fruits with internal ethylene over 0.2 ppm = indicates when ethylene begins to influence fruit ripening and it cannot be held back easily after this is reached.
  • Color % = the visual percentage of red color from 0 to 100; range is of all fruits tested
  • Background color: 5 = Green, 1 = Yellow; range is of all fruits tested.
  • Firmness in pounds pressure = measured with a Güss Fruit Texture Analyzer; range is of all fruits tested.
  • Starch: 1 = all starch, 8 = No starch; range is of all fruits tested. Using Cornell Starch Iodine Index Chart.
  • Brix = % sugar measured with Atago PAL-1 Pocket Refractometer

Looking for more? View Michigan State University Extension’s Apple Maturity page for regional reports throughout the state and additional resources.

Suggested firmness and starch index levels for long-term and shorter-term controlled atmosphere (CA) storage by variety.

Variety

Firmness (pounds)*

Starch Index*

Short CA

Mid-CA

Long CA

Mature

Over mature

McIntosh

14

15

16

5

7

Gala

16

17

18

3

6

Honeycrisp

15

16

17

3.5

7

Empire

14

15

16

3.5

6

Early Fuji

16

17

18

3

7

Jonagold

15

16

17

3.5

5.5

Jonathan

14

15

16

3.5

5.5

Golden Delicious

15

16

17

3

6.5

Red Delicious

16

17

18

2.5

6

Idared

14

15

16

3.5

6

Fuji

16

17

18

3

7

Rome

15

16

18

3

5.5

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