Quality
Raw material - fresh fish
Raw material - frozen fish
Preparation
Brining
Hanging
Smoking in traditional kilns
Smoking in Torry type kilns
Packing
Storage - short term
Storage - long term
Transport of frozen smoked fish
Hygiene
To produce first class smoked white fish, remember - use only good quality fresh fish or frozen fish. Take care throughout the smoking process. Handle the products properly afterwards.
Cook and taste your products; appearance alone cannot tell you enough - keep a sample for twenty-four hours at 60°F, to simulate what the customer gets, before you try it.
Use only good quality fresh fish.
Keep the fish well iced after landing until they reach the factory.
Check fish temperatures on arrival and re-ice them where necessary.
Don't put ice just on top of the boxes - put ice between each layer of fish as well.
Don't depend only on a chill room to protect uniced fish - both ice and chilled storage are necessary, especially overnight.
Check fish temperatures often: if they are not very near to 32°F, then improve your practice.
Reject any unsuitable fish discovered during handling - greasers and diseased fish make distasteful smoked products.
Frozen fish for smoking must have been frozen quickly and stored at minus 20°F for less than a year.
Whole cod should have been frozen within three days of catching, haddocks within two days, and should have been kept in ice until frozen.
Fish frozen as fillets cannot be satisfactorily smoked.
Wash whole fish in a spray of running water before processing.
Remove all slime, blood and scales from the cut surfaces of the fish - otherwise you won't get a good gloss.
Brining gives the smoked fish its attractive gloss.
Brining time depends on size and thickness, and may take from a few minutes for a small fillet to fifteen minutes for a large one in 75 per cent saturated brine.
Avoid variations in brining time of the fish within each batch - get the whole batch in or out quickly.
Do not crowd too many fish into a brining tank at one time.
Brine strength decreases with use - because fresh water from the fish dilutes it, and because some salt is absorbed by the fish.
Test brine strength regularly with a brineometer.
Stir in solid salt to keep brine strength at about 70 per cent to 80 per cent saturation.
Don't try to bring brine up to strength by adding 100 per cent saturated brine.
Taste samples of your product to judge the brining process - extra saltiness has only slight effect upon keeping quality and may spoil the flavour - products with more than 2 1/2 per cent salt are too salty for most people.
If brining fails to bring out the gloss on thawed frozen fish, then the fish have been cold-stored too long at too high a temperature - properly frozen and cold-stored fish can yield a very attractive product.
Make new brines regularly - daily if possible and every two or three days at the most.
Stale fish will pollute fresh brine.
Remove scum from the brine at regular intervals.
Hang your fish immediately after brining before the gloss begins to set - split brined fish will stick together if kept overnight in baskets.
Allow the hung products to stand for several hours, preferably in a chill room not lower than 28 °F, before smoking - this ensures a very attractive gloss.
Inspect the hung fish for blemishes - remove those with blood marks, scales, dirt or parasitic worms.
Keep kilns clean - tar deposits can flake off and fall on fish, and a dirty kiln can easily catch fire.
Inspect cowlings and louvres regularly - see that they work and don't let in water - fit a permanent ladder for inspection purposes.
Check that bottom doors, which control air flow, move easily and fit tightly.
A good quality product that keeps well must lose 12 per cent to 14 per cent of its original weight during smoking.
Keep kiln fires under control - don't allow them to burst into flame since the lower rails of fish may cook.
Never damp the fires with buckets of water.
Never allow ash to accumulate.
Don't use very wet sawdust - mouldy mush or dust may cause the fish to taste of mould.
Don't reload the kiln with fish several hours before smoking begins - the warmth retained by the brickwork can spoil the fish.
Don't hurry the smoking process - 'flying' can result in a case-hardened product.
Inspect and grease all moving parts about once a month - remember to look at dampers, hinges, fastenings and trolley castors. Fan motors and bearings should be looked at once or twice a year by a competent electrician.
Inspect and service thermostat occasionally. Clean out the ducts at least once a week, using a scraper.
Never pack smoked fish while still hot - leave them to cool on racks with plenty of room between tenters for air to circulate.
Allow two hours in still air for large loads of fish to cool - use fans if you want to reduce this time.
If you use a chill room to cool the fish before packing, don't let this delay distribution for a day, or the advantage gained by chilling may be more than offset - warm fish put straight into a chill may sweat badly and lose gloss.
Use a paper liner when packing smoked fish in wooden boxes - cover at least the top and bottom and preferably surround the fish completely - this helps to reduce growth of moulds, improves hygiene and adds to appearance.
Keep boxed smoked fish overnight in a chill room.
Use plenty of spacer sticks between boxes to allow cold air to
circulate.
Boxed smoked fish may be kept for up to three days in a chill
before dispatch - without a chill do not keep them more than twenty-four
hours.
Freezing is often economic even for immediate
dispatch.
Freezing is essential if you are storing your smoked fish for more than three days before dispatch.
Use a properly-designed air blast freezer - do not attempt to freeze boxes of smoked fish by stacking them in a cold store.
A suitable freezer should operate at an air temperature of - 20°F or below, and have an air speed of at least 500 feet per minute.
Space out the boxes to allow the cold air to blow between them.
Distribute the boxes equally across the air stream so that the cold air cannot bypass the product.
Smoked fillets can be packed and quick-frozen without boxes in the same way as fresh fillets.
Finnans can be packed and quick-frozen without boxes in much the same way as kippers.
It is cheaper in the long run to quick-freeze all classes of smoked fish without boxes because of the savings in storage space and on the cost of the wooden boxes.
Keep frozen smoked fish at a temperature of - 20°F or below.
Do not use the cold store to complete the freezing process - the temperature of the product should be down to that of the store before it is put away.
Frozen smoked fish can be allowed to thaw out on the way provided it is treated at the receiving end in exactly the same way as fresh smoked fish.
Use insulated vans if the fish are to remain frozen.
Dry ice, solid carbon dioxide, may help when transporting small quantities, but for large loads of 100 stones or more it is of little value on journeys of less than twenty-four hours.
Factory floors should be of a hard impervious material that can easily be cleaned.
Do not tolerate cracked concrete floors.
Wash all floors daily and remove any offal.
Walls should be tiled to the ceiling and be cleaned regularly.
Splitting and filleting boards must be completely free of slime - repeated washing is essential - keep your knives clean too.
Drains should be inspected daily - they should be easily accessible and be cleaned out regularly.
Open drains outside the building should be covered.
Offal Bins should be emptied every day and scrubbed with a suitable detergent.
Containers for handling fish should be cleaned daily immediately after use.
Brine Tanks should be cleaned with a suitable detergent after emptying out old brine, and scrubbed thoroughly with hot water.
Hose out the tank to remove all traces of detergent and filth, then scrub with a disinfectant solution of hypochlorite.
Use two cupfuls of hypochlorite to a gallon of water - this gives about 1,000 parts per million of available chlorine.
Apply the solution liberally, leave for twenty minutes and then fill up with fresh water to make new brine - there is no need to wash off the traces of hypochlorite.
Wooden or stone brine tanks are not completely cleared of bacteria in this way - make your tanks of stainless steel or some other suitable material.
Sticks and Banjos should be scrubbed with a hot alkaline detergent about once a month.
Stainless steel banjos do not rust, are easier to keep clean and last longer than mild steel banjos or wooden sticks.
Detailed information on most aspects of fish handling and
processing may be found in the publications of Torry Research Station.
