02. Karasumi; 50 Days Later | KAISEKI APPRENTICE JON

This will be a long post as I go through the step-by-step process for those who were asking. 

Note: The first decision is buying the Borako (fresh mullet eggs). Depending on the method of slaughtering, the condition roe sacks can vary quite a bit. The Ikejime/Shinkenuki process will drain a great deal of undesirable blood out of the eggs, making the first few steps much easier. 

Step 1: Purging the blood

The remaining blood will turn black, bitter and foul smelling during the curing process. Get all the blood out! I use a needle attached to a faucet-hose to flush the blood out of the veins. You do not need this tool but it will save you time. The alternative is to poke tiny holes in all the veins and anywhere where blood is visible in the roe sacks. Then, soak in 2% salt water for a day or so. Now, using 2 perforated trays and a weight, gently press out the absorbed liquid; the blood will be squeezed out with it. Repeat the soaking, poking and pressing process until the roe is completely free of visible blood (2-3 days depending on slaughtering method and condition).


Step 2: Salting 

The 2% salt water is used to slow bacterial growth and prevent excessive draining of flavour from the eggs. During the soaking, the roe still needs to be cured. Take the thoroughly drained, pressed roe and proceed to rub down with as much sea salt as you can get to stick to the roe (a good 1mm layer all the way around should be fine). Put the Borako back into the perforated pan press and cure for at least 2-3 days depending on the size. 

Step 3: De-salting

I’ve seen a few people on Instagram stop at this point and produce salty fish rocks. Karasumi is a much softer product that can be eaten as is, sliced. Such as the salty level and moisture content of a French cured saucisson sec. To remove the salt, the Karasumi is soaked in either Sake (Nihonshu) or Shochu. Not only does this lower the salt content to an edible level but it provides great flavour while controlling bacteria. Removing the salt is a little tricky because you don’t want to remove it all, otherwise, the Karasumi will not cure properly and spoil. After salting, I used 1440cc of Amabuki Junmai Kimoto for 4 very large karasumi and soaked for 2.5 days. 

Step 4: Pressing

After soaking, once again press out as much liquid as you can from the Karasumi. Make sure they are oriented with the artery down and centred in the middle of the lobe. This process

will produce their final shape.

Step 5: Drying

Under refrigeration (or Kyoto winter), dry the Karasumi on a perforated sheet with nothing on top of them. If you are drying outside, make sure you have a net cage to keep insects and birds away. During the drying process, make sure to flip the Karasumi every day to ensure even drying and to prevent mold growth on the bottom. Expect 30-50 days depending on the size and desired hardness.

Step 6: Equalizing (optional) 

As the Karasumi dries, moisture is tamed from only the outside, so if you eat it right away (after the drying is completed), there will be a moisture gradient from the hard outside to the saturated inside. For a more consistent product, leave the karasumi in an airtight container for another week. Vacuum packing is an alternative that will take about 1/5 of the time. You now have the perfect Karasumi



This article was written by Jon Klip. Please visit here to see his recent work on Instagram.