ISSUE # 219 January 22, 2010
Most of the inquiries we receive in regards to carrots have to do with dewatering waste. These come mostly from carrot peeling operations, but producers of baby carrots also
have a good application. In all cases, much greater reduction of moisture content is achieved if hydrated lime is mixed with the carrot waste. All of this is covered in
Pressing News #193, Potatoes and Carrots.
A less common application is the production of carrot juice.
The novice approach is to shred the carrots and then run them through a screw press. Carrots typically are 88% moisture, with 6o to 8o Brix. This will produce only a small
yield of juice, and the press cake will have about 85% moisture content. The operation is not commercially practical.
To produce carrot juice it is necessary to not only shred, but also blanch the carrots. Blanching is partial cooking, like parboiling. Blentech and Hosokawa/Bepex offer
blanchers designed for the application. Steam, in the amount of 15% by weight, is added to the carrots. When this is done, press cake with a moisture content of 80% can be
achieved. Juice yield goes up, we have been told, to 40% by weight.
The process can be fine tuned using a variety of available equipment. We have seen finishers used for the initial juice extraction. One installation was using a Goodnature
press to take blanched carrots down to 85% moisture content; a screw press took the Goodnature cake on down to 80%. All of this was replaced with a centrifuge. Enzymes
may also work wonders, when added ahead of either screw presses or decanters.
It was found that double and even triple pressing improved yield. That is, the cake after the first press was run through a second press. In the case of third pressing,
a considerable amount of carrot frit came through the screen of the screw press. Surprisingly, the moisture content of the press cake produced in these multiple pressings
stayed about the same, close to 80%.