Earlitreat Peaches |
We are just about one week off from picking Earlitreat peaches, the first tree fruit to be harvested at The Orchard. Right on its heels are the apricots. The temperatures this time of year are very close to the temperatures we had last Spring; cool.
Cool weather does not tend to develop the sweetness and flavors that hotter weather does in many of our early fruit. Cool weather may also affect how the pit of stone fruit develops. Sugar content will be low unless temperatures start to rise consistently into the 90's. Total acidity and other flavor factors are also affected. The high temperatures of our desert usually cause our fruits to have very high sugar contents. The salinity of our soils may also increase sugar contents.
Refractometer |
Refractometers can be purchased from several vendors such as Orchard Valley Supply, Spectrum Technologies, and other online sources.
A few drops of juice are squeezed from the food that you are testing using a garlic press and placed on the prism of the refractometer on the bottom left. If you have a handheld refractometer like the one above you look through the eyepiece and determine the Brix reading. If you have a digital refractometer, you calibrate the refractometer using distilled water, and press a button to have it analyze the sample and determine the Brix reading. Be sure to clean the prism each time a Brix reading is made.
REFRACTIVE INDEX OF CROP JUICES
CALIBRATED IN % SUCROSE OR °BRIX
Fruit | Poor | Exc. | Veggies | Poor | Exc. |
Apples | 6 | 18 | Asparagus | 2 | 8 |
Avocados | 4 | 10 | Beets | 2 | 12 |
Bananas | 8 | 14 | Broccoli | 6 | 12 |
Cantaloupe | 8 | 16 | Cabbage | 6 | 12 |
Casaba | 8 | 14 | Carrots | 4 | 18 |
Cherries | 6 | 16 | Cauliflower | 4 | 10 |
Coconut | 8 | 14 | Celery | 4 | 12 |
Grapes | 8 | 24 | Corn Stalks | 4 | 20 |
Grapefruit | 6 | 18 | Corn, Sweet | 6 | 24 |
Honeydew | 8 | 14 | Cow Peas | 4 | 12 |
Kumquat | 4 | 10 | Endive | 4 | 10 |
Lemons | 4 | 12 | Escarole | 4 | 10 |
Limes | 4 | 12 | Green Beans | 4 | 10 |
Mangos | 4 | 14 | Kohlrabi | 6 | 12 |
Oranges | 6 | 20 | Lettuce | 4 | 10 |
Papayas | 6 | 22 | Onions | 4 | 10 |
Peaches | 6 | 18 | Parsley | 4 | 10 |
Pears | 6 | 14 | Peanuts | 4 | 10 |
Pineapple | 12 | 22 | Peas, Eng. | 8 | 14 |
Raisins | 60 | 80 | Peas, Field | 4 | 12 |
Rasp. | 6 | 14 | Peppers, Bell | 4 | 12 |
Strawb. | 6 | 16 | Peppers, Hot | 4 | 10 |
Tomatoes | 4 | 12 | Potatoes, Ir. | 3 | 7 |
Waterm. | 8 | 16 | Potatoes, Red | 3 | 7 |
Potatoes, Sw. | 6 | 14 | |||
GRASSES | Rutabagas | 4 | 12 | ||
Alfalfa | 4 | 22 | Squash | 6 | 14 |
Grains | 6 | 18 | Turnips | 4 | 10 |
I have had some comments regarding why Brix is impacted by temperature. Lets look at some examples. Those who live on the cool coastal climates complain about their apricots or peaches not being sweet. Yet here in the desert we can produce some very high sugar contents from the same varieties that were insipid in Portland or Seattle. It is widely known that in desert locations wine grapes produce high sugar content with low acidity. While in coastal areas they can produce wine grapes with high acidity but lower sugar content. This is a function of two factors; sugar development due to high light intensities and the burning of sugars due to respiration. If our desert climate has a problem it is not due to sugar content but lack of acidity and having a good sugar/acid ratio in our fruits. But sugar content of superior varieties is sky high in the desert.
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