Weight Loss Query

[Batman]

As another poster on the forum my salmon curing/smoking attempt failed to get anywhere close to 17-18% weight loss which 'must' be achieved according to Erlandson.

Erlandson prefers to wet cure salmon which he suggests only reduces weight by 1.5-3% which implies that the balance of weight loss is achieved through long (24-60hrs) cold smoking at his suggested 26C. This raises a couple of queries, firstly, are home smokers ever likely to achieve the target weight loss, if so how? Secondly, what is the impact of (only) achieving less than half of the (must achieve) weight loss? Is it quality or product life?

Anyone any thoughts?

[wheels]

Batman
Please tell me if I am being super sensitive here, but my post was not a Criticism. I repeat it here:

Batman
I have only cold smoked trout - keep meaning to try some salmon (IMO the trout is better hot smoked).

Is your salmon nice and firm? I ask because Keith Erlandson (Home Smoking and Curing) advises a 8-9% weight loss after (dry) curing with an overall weight loss of 17-18% after a period of between 24-60 hours smoking. If my experience with trout is anything to go by, this would produce a very smoky product. I prefer the sound of yours.

I wonder, firstly, whether the same weight loss is necessary if (say) the finished product was vac packed for storage or eaten shortly after smoking and, secondly, how much weight loss is required for the product to be 'safe'? I am aware of certain advice about 'flash' freezing to get rid of any parasites, but taking this into account, and in the knowledge that salmon is often eaten raw in Japanese dishes, I would assume that there isn't any other particular hazard involved - can anyone advise?

Phil

You'll note the part where I say that your method looked better to me:

I prefer the sound of yours.

As someone who wants to learn about all aspects of curing and smoking this was asked as a genuine question - If salmon is safe to eat raw why must it lose 17% to be safe smoked?

The reason I ask? Because I would have done exactly the same as you and want wiser more experienced guys to confirm that this is safe.

If I have mis-construed your post I apologise in advance.

[Oddley]

Hi Batman, the following link might be of some help to you.

http://seafood.ucdavis.edu/pubs/smoking.htm

[Batman]

Wheels my apology. The confusion comes about because having posted my first post I started the second post and got distracted by other things, came back later completed the second post and went to bed without realising that you had already responded to my first post!

Makes mental note to finish posts asap

[Batman]

Thanks Oddley (and Wheels) for posting the reference. It seems to confirm Erlandson's method without really explaining why the need for such long smoking times which are pragmatically impossible to achieve for home smokers.

Given that in business time is money, you would have thought that commercial smokers would only use extended times IF there was a solid business case. Maybe this is just one of those 'its always been done like that' instances or maybe there is a good reason for long smoking times. I sure would like to know.

[Oddley]

Batman, please remember that smoke is in it's self a preservative, all the time it's hanging, it's drying. If it's AW <= 0.85 it will last much longer than lightly smoked wet ie AW >0.85. Also if the brine concentration in the fish is >10% this will inhibit the growth of most bacteria.

Therefore, the fish should last weeks rather than days.

[wheels]

Wheels my apology. The confusion comes about because having posted my first post I started the second post and got distracted by other things, came back later completed the second post and went to bed without realising that you had already responded to my first post!

Makes mental note to finish posts asap

Phew, thank goodness for that.

I found this document from The Food and Agriculture Organization of the United Nations. I guess it can be taken as authoritative. The link is to the part on smoking, but the whole document is worth a read.

Part of our questions are answered by the difference between traditional and mechanical kilns - the timings for mechanical kilns are about what we think is about right. The only problem left is that they seem to expect a 16-18% overall weight loss (curing & smoking combined) during this period. With 7-9% loss achieved by smoking: a period during which your salmon lost little or no weight. However, the article does go on to mention continuing drying after the smoking period, which may be the answer.

Edit - added 19.12 -1-6-08
From Galloway Smokehouse website

The sides are smoked for anything up to 48 hours in oak smoke. During this time the sides need to loose 15% of their moisture, and obtain the golden hue and traditional texture. The sawdust is only allowed to smoulder, so a layer of ice is placed on the sawdust and as this melts it damps the surface layer of sawdust. This damp layer stops the sawdust from bursting into flames and so cooking the fish. The maximum temperature can only be 30�C so it is a difficult process in warm countries.

Do any other forum members monitor weight loss during smoking? (Oops, I can feel a few funny comments coming on ).

If so can they post their findings for comparison please.
Phil

[saucisson]

I was about to move the whole thread over to dietary chat

Dave

[Batman]

That FAO document is interesting, quite a few similarities with Erlandson. The good news is that we seem to be doing the dry salting ok, even with the reduced amount of salt in Saucisson's recipe, as we can get the 7-9% initial reduction.

Perhaps the difference is purely down to the smoking temperature, they suggest slightly raised temperatures above ambient (FAO 27C plus 30 mins at 33C, Erlandson 26-32C) whereas my temps were around 20C. I don't think I could achieve this temperature in my home made smoker, though maybe someone with a Bradley could.

Unfortunately, there's still no explanation of the 'science' behind the 15-17% weight loss target.

Still hoping for an explanation.

[saucisson]

Unfortunately, there's still no explanation of the 'science' behind the 15-17% weight loss target.

Still hoping for an explanation.

Do you mean how to get to 15-17%, or why do we need to get to that figure?

Dave

[Batman]

Dave, its the 'why' I'm interested in, particularly in relation to the impact on the product of NOT achieving the recommended weight loss.

[saucisson]

Oddley gave the reasons earlier, it's all about longevity of your product. Above that magic number the fish is still basically salted fish, it will last longer than untreated but should still be considered fresh. Below that number the reduced water content inhibits or abolishes the growth of bacterial organisms likely to cause it to go off.

Like many modern commercial products the curing and smoking is as much about flavour as preservation these days, hence the need to keep it in a fridge after purchase. A drier saltier product may be less desirable to the modern palette.

A high water content smoked salmon stored in the fridge in layers of grease proof paper will last a few days and then go off. A low water content fish will continue to cure and mature but ultimately turn into shoe leather.

Dave

[Batman]

Thanks Dave. Are you aware if there's any published science behind this or is it something that has just become embedded in practice as a result of experience. I'm not disputing it I'm just really curious to try and understand the process.

I vac packed and am refrigerating the bulk of the fillet for a 'do' this coming friday - 7 days after smoking, do you think it will still be ok to eat, I'd hate to poison my guests. Should I freeze it? I've tasted the trimmings which are very good.

Cheers

[saucisson]

It's a mixture of science and established practice. I'm wading through some stuff at the moment that someone kindly sent me, If I can pull out any nuggets for you I will post them here.

What weight loss did you achieve in the end or don't you know? I would have thought 7 days vac packed would be OK in the fridge even if you didn't get down to <0.85

Dave

[wheels]

Dave, the knub of my question is "Do we need to achieve 15-17% weight loss to make a safe product regardless of proposed storage time/method?"

I ask because smoked fish differs from fresh fish in that you wouldn't subject fresh fish to 5-10 hours sitting in the temperature 'danger zone' whereas we do with smoked.

Phil