Ingredients
I have a press. This is just a little bigger than A3 size and is made, with adaptions, from an old trouser press I purchased on ebay.
You will also need plenty of dry and uncrumpled newspaper, several fine mesh nylon sheets, a spray bottle, some water, and finally, of course, some dried and flaked seaweed
Method
To prepare the latter, ideally collect in spring or summer on a warm sunny day.
Rinse it in the sea and also at home if you fancy, squeeze out as much water as possible, pull open the scrunched up pieces and lay out in a single layer on a sheet in the sun to dry.
Only do this during daylight hours.
Turn all the seaweed over half way through and bring in an hour before sunset (even if it’s not fully dry) to prevent it getting damp. Seal in an air-tight bag and lay out again the next day if necessary. Do this until it’s crisp. In this country it’s rarely hot enough to get it so crisp in the sun that it will crush and break up when you squash it up. To get to that level of dryness, finish it off for 10-60 minutes in a low oven (with the door open), in a food dehydrator or on top of a radiator.
After that, crush it all up with your hands in a large bowl or bucket. For the thinner seaweeds it should be possible to do all this by hand, nevertheless, after some initial crushing, it can be helpful to put the seaweed in a food processor to grind up a little further. For best results flakes should be between 1-5 mm across; most being 3 mm.
Trouble shooting
Help! Day 3 of pressing and my nori sheets are going mouldy!
Yes, during my first attempt to make these the tell tale signs of white mould spots started to form from the centre of the nori, spreading out with each passing day, whilst , in denial, I continued to convince myself that these spots where just benign salt deposits forming as the sheets dried. We see what we want to see!

Obviously mould is unwanted. In order to prevent this there are a number of variables to consider. Taking into account just one of them may solve the problem; adjust your technique to address all of them and success is guaranteed.
In order to grow, mould needs water, food and time, and will occur if the sheets aren’t dried quickly enough. In a solid press like mine the sheets dry in 3-4 days in an averagely warm room. Ideally drying time should be no more than 3 days and ideally two. The time taken to draw out the moisture can be reduced in 3 main ways: Change the newspaper more frequently – 3 times a day rather than 2. Increase the temperature by placing the press in a warm airing cupboard or on top of a radiator. Use a press that allows for better moisture evaporation. For example, most seaweed presses are of the wooden lattice design and are tied up with straps. The problem with that is that for the purposes of nori sheet making you can never get it tight enough. An ideal design would be a lattice wooden or metal press that can be screwed down like mine. Must make one of these…….
Another idea if after a day or two you spot the early signs of mould is to stop it in its tracks by lifting the half dried sheets from the press and drying quickly by some other means, such as using a radiator, food dehydrator or low oven. Do dry them flat if doing this and be sure to return them for a final press before they become too dry and brittle to handle.
I also found that liquidizing a couple of garlic bulbs in my water spray greatly reduced the likelihood of mould forming, although, of course, it left a garlic flavour that might not always be wanted.
Finally, if you do have a problem with mould, don’t use the same newspaper for your next batch of sheets, and wash and dry the nylon sheets very well before re-use.
Help! My sheets are dry and look great in the press but when I take them out they just disintegrate.
Several things could have occurred here. It could be one of, or a combination of the following reasons: your flake size is too small; your sheet is simply too thin; the flakes are just too thick; you are using a plant material that no matter how you prepare it, it simply will never hold together. A good example is lacto-fermented wild garlic leaf. It tastes delicious, dries, flakes and sprinkles well, looks like it’s held together but disintegrated. In the case of wild garlic and some other plant leaves this problem can be got around by creating the sheets by laying down fresh leaf material – a bit of a fiddle, but worth it. If using fungi, the building up of sheets by laying down finely chopped cooked fungi is the only method I’ve used that works. Drying and attempting to flake fungi generally results in an unpressable powder or big and unpressable hard granules.
Help! I’ve pressed the sheets for 3 days and have just removed them from the press to put over the radiator/food dehydrator/low oven so as to remove all moisture and prevent mold formation, but now they are not flat, are very brittle and I can’t flatten them out without breaking them!
or….
Help! My sheets are dry and hold together well, but when I come to roll them to make sushi they crack and break.
Okay, yes, this happened to me and, yes, it was bloody annoying! If you have a room in your house that is fairly damp, just leave the sheets there for an hour or two (or even a day or two) to take on a bit of moisture from the air; alternatively place on a tray and leave outside (assuming it’s not raining or snowing)!! Both these methods only really work during the cooler months of the year. Alternatively, soak a tea towel and wring out VERY well so that it’s just damp. Carefully lay over the nori sheet for a few minutes. Finally, being very careful not to over soak – and from a distance of a few feet – you can spray a few pumps of water over the sheet and leave for a few minutes.
A completely different technique that works very well is to add a tiny amount of oil during the process of creating the sheets. To do this, make the sheets in the usual way, i.e. by spraying a fine mist of water (not oil) over the sheets and then press for two days. After that, before pressing again, spray over about 4-5 light mistings of fine oil spray on each side of the nori sheet. Actually, 4-5 sprays each side is only appropriate if you have a spray nozzle that works with oil. I’ve used the oil spray ‘bottles’ you can buy in the supermarket – weird people worried about their fat consumption use them (apologies if that means you – weirdo) ! If you’ve been spraying with a nozzle designed to spray water or alcohol, trying to use it to spray oil will result not in misting but, rather, in jets of oil as if you’re firing a water pistol. Not to worry though. Simply mix olive oil and water in a 1:1 ratio and shake well before spraying. Using this method requires about 20 sprays each side of the sheet. It is important to bear in mind that such oil spraying should only be done after the sheet has been pressed first and certainly not during the process of building up the sheet initially, to do so would adversely affect the binding of the sheet so that it would be more likely to disintegrate. Note: If doing this, especially if you intend to store the nori sheets for quite a while, don’t use an oil such as walnut or hazel nut oil as they are more likely to go rancid than other oils, e.g. olive oil. Also be aware that when using the oil method it can sometimes be hard to tell if all moisture has been removed. As in most things, practice and experience makes perfect!
By the way, you might be wondering why, if the oil method is such a good technique I don’t just write about that and thus avoid all the potential problems that can result (if you’re not careful) from using water spray only? There are two reasons. In the first place, I’m trying to mimic traditional non-industrial processes, i.e. the way I suspect (without much evidence other than a strong intuition) that I would imagine the Japanese used to make nori sheets for hundreds of years. Secondly, in 2013 (from 1st April or May – not quite decided) I’ll be attempting to live for a year entirely on wild/foraged foods. For me, the creation of these nori sheets is part of the detailed experimental research I’m doing in preparation for that year. In terms of fats/oils, so far I’ve managed to extract walnut oil (that goes rancid after prolonged storage) and badger fat (that I can’t get to form a spray). Of course, olive oil works really well, but I won’t be able to make that in 2013 in the UK.
Help! I think I’ve got the flake size right but am having trouble creating sheets of an even thickness.
Several factors lead to this problem. Make sure that the fabric squares that you are sprinkling the seaweed on to are completely flat (iron them if necessary). Also make sure you have covered the fabric with a fine mist of water spray. When it comes to sprinkling the seaweed, using a sieve can help (although most have holes that are too small). Also, sprinkling a very even thin layer first, then spraying (water) before adding a second layer is better than trying to get a full thickness in one covering. After that, if any background cloth can be seen, just take a pinch of dried seaweed and cover individual gaps. Spray well a final time waiting a few minutes for the water to be absorbed before pressing.
Help! My sheets turned out perfect but I’ve stored them for a month and they have gone mouldy.
After all that effort this would be a frustrating outcome indeed. I store mine in the same way as you’d find nori sheets when you buy them in the shops, that is, stored flat and completely dry in a plastic bag with an air-tight seal. Similarly, as many commercial producers do, you can put a small pack of silica crystals in with your nori sheets to attract any unwanted moisture. The use of silica crystals is very useful if you initially used seaweed that was only rinsed in the sea and, hence, has a substantial amount of moisture attracting salt in/on it. Of course, you could just have rinsed in fresh water initially. Yes, that’s obvious, but sometimes the nori does taste better when the seaweed has a natural coating of sea salt, and in actual fact no matter how you initially prepared the nori it will still attracted water and potentially degrade if you don’t take precautions.
Hi. Interesting experiments – I admire your tenacity.
Is there a bit missing from the description of your process? It seems to jump directly from ‘grinding dried weed’ to ‘troubleshooting’.