On Sat, 19 Apr 2008 07:05:28 -0700, gene wrote:

Bruce in Bangkok wrote:
First of all I live in Thailand where the source of wine making
equipment is strictly limited. To date I have been "crushing" grapes
by hand, stomping, and rubbing through a plastic basket (similar to a
milk crate) and to be frank it is a lot of work and I would like to
build a crusher, possibly a crusher/destemer.

Does anyone have plans, a photograph, or any other data about the
internal parts, or any other information, regarding crushers and how
they are function?

I presently envision two geared rollers with adjustable spacing but
what material for the rollers? Can they be smooth or do they need
serration? What about the destemer portion?

I have a background in engineering and metal fabrication so the actual
building will not be a problem, it is in the details where the devils
lurk.

Any assistance, no matter how rudimentary, will be very greatly
appreciated.


Bruce-in-Bangkok
(correct email address for reply)

The grapes would tend to slip on smooth rollers; it helps to have a
serrated (or at least very rough) surface to get a bit of a grip on the
grapes to pull them through the crusher rollers.

The roller construction material is not too critical. You want to avoid
materials that a
1) too soft
2) absorb liquids (bacteria grows in them over time if not
well-sanitized after each use; wood is a good example of this)
3)degraded by repeated exposure to your sanitizing solution.

304 stainless steel is ideal, electroless nickel plated steel is OK,
brass and aluminum are too soft and easily damaged, bare iron and steel
are not good because they rust. Avoid coated steel [i.e. galvanized,
tin-coated, cadmium plated, chromate-dipped (a golden, often iridescent
color)]; these coatings leach into the juice.

Plastics such as nylon, HDPE (high density polyethylene), polyurethane
and delrin will also work nicely. You want a durable plastic, one that
is not easily damaged if a hard object falls in between the two rollers
(like a wayward rock or tool or such).

Natural rubber is not a good choice; many kinds of sanitizers degrade
it. Synthetic rubbers such as EPDM, EPR, viton and silicone will work
(though EPDM and EPR are slowly degraded by many sanitizers).

For the destemmer cage, I'd use 304 stainless steel. The perforation
holes need to have radiused corners, with the convex surface facing the
inside of the cage. This is key to minimize cutting/tearing the grapes
instead of plucking them off the stems. The optimum hole size and
spacing is chosen based on the size of the grapes and density of the
cluster... something on the order of 1/2 to 3/4 inch holes on about 2
inch centers is my recollection. I'll need to measure one on Monday to
confirm it.

Gene

I think that the destemer may be overly complex to build since, as you
say, the hole size is dependant on the berry size and that would mean
either a series of graduated holes or several different sized screens.

I had been thinking of stainless tubing rollers but was having second
thoughts about the smoothness. I hadn't thought about plastic - nylon
and delron is available here in most hardware shops. I'll have to
check on prices.

I usually process 150 - 200 lbs of grapes at a time so this thing
doesn't need to be a massive device and I'm presently thinking of
something that is hand cranked and sits on top of a barrel.



Bruce-in-Bangkok
(correct email address for reply)