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Why did my homemade lobster stock smell so foul? Help!

A few weeks ago I boiled two lobsters for myself and my boyfriend and then returned the shells (head innards included) to the pot along with the original boiling water, a bit more water, an onion, celery, a carrot and herbs. This was my first time attempting lobster stock.

I brought it to a boil and simmered it for quite a while. (I did not roast or broil the shells before bringing them to a boil, as some recipes suggest, since I had just cooked the whole lobsters.) I simmered the whole thing for probably two hours while I watched a movie.

Afterward I removed the solids, strained the stock somewhat and reduced it way down, probably wrongly -- because it then turned an unappealing muddy gray color. Oh well, it would still taste lobstery, I figured. I strained it a few times through a sieve lined with cheesecloth, poured it into a plastic container and put it in the fridge.

A day or two later, when I looked in the fridge, I noticed that it had a lot of sediment at the bottom, similar in proportion and appearance to the sediment that forms at the bottom of a carboy of fermenting wort when I home-brew beer.

I opened up the container with plans to strain the stock some more, but the stuff was head-boltingly stinky -- and not like fish. It didn't even smell like food, really -- more like some weird chemical concoction, or the damp, stuffy smell of subway stations in disrepair. It was seriously gross. It had smelled similar but not nearly as strong right after I'd made the stock.

I was afraid to try it, but I diluted a sip of the concentrated stock with water, heated it and tried it. It tasted slightly odd and musty but not foul like it smelled. It still tasted like stock, but the smell, sediment and color -- and what I'd read about possible seafood contamination -- frightened me. I regretfully dumped the entire batch, and the unsalvageably smelly container.

So... What did I do wrong? Why did the stuff smell so incredibly awful? Was it because I didn't sufficiently strain the stuff right off the bat? Was it because I overreduced it? Was it because I didn't cook the shells in the oven? Or should I have removed all the stuff from inside the heads, or anything else, before boiling the lobster carcasses?

Given how cheap lobsters are (and given that I'm going to Maine soon), I'd love to know how to avoid my awful lobster stock-making screw-ups next time. Thanks!

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  1. no clue but i'm curious to know what you've found out...

    1. I was going to make lobster stock on new year's day and checked probably half a dozen recipes to see what approach I wanted to take. Each of those recipes said to clean the bodies, but each of those recipes seemed to have a different idea of what that meant. Nearly all said to remove the gills. Many said to remove the sand sac from between the eyes; a couple said to remove the lungs and stomach; and at least one said to remove the tomalley. Okay. I know tomally and gills; but I couldn't figure out what the rest of those parts were. So I cleaned it all out. And using Eric Ripert's recipe on Epicurious, I ended with the best lobster stock I've ever made.

      I suspect your offender was at least one, if not a combination, of the above removeables. One of the recipes I read, but I can't locate it again now that I'm looking for it, specifically mentioned that including one (or was it more?) of those things will give you a cloudy stock with an off taste.

      Try the Ripert recipe next time.


      I made the two cups of stock and froze that and then made the remouillage. Hadn't done that before and just loved the idea. I was surprised by how much flavor was still left in the shells.

      6 Replies
      1. re: JoanN

        I make lobster stock using a very simple recipe with shells from cooked lobsters. The only thing I remove is the sac between the eyes; I like all the lobster meat that's in the nooks and crannies. I chop onion/carrot/celery and use fresh water. Using the lobster cooking water may have been the thing that made your stock funky.

        Edit: I don't cook the stock very long. 30 minutes at most.

        1. re: Gio

          I certainly didn't mean to imply when I said that I cleaned the shells that I removed any meat (although, I must say, that by the time I'm done with a lobster there's damn little meat left). I just clean out anything "loose" and mushy.

          Really interesting that you don't remove anything but the sac. (And you'd think that with all the lobsters I've eaten I'd know exactly what that is--but I don't.) As I noted, nearly all the recipes I read said to remove at least the gills as well. Wonder if it's just the sac that could be the culprit. And I hadn't even caught that the OP used the original water in which s/he cooked the lobsters. That probably didn't help any.

          1. re: JoanN

            LOL Joan... I've done serious damage to lobsters all my life. But lately we've been buying 2+ pounders and after the claws, knuckles and tails plus any roe or tomally, I'm not interested in the legs and bodies. If the bodies have lots of meat left I make a lobster red sauce with them. But everything else, the empty shells as well, go into the stock. Here are 2 diagrams I find invaluable:

            1. re: Gio

              So, is what everyone seems to call the "sand sac" actually the brain?

              1. re: JoanN

                From the diagrams I say yes. Wouldn't want to eat that one.
                I've hard it called various names over the years, but always have heard to stay away from it, although there is some choice meat near or behind it, I never ventured there. There are some other organs that come out when you pull out that whole section.

                1. re: Gio

                  Evidently not. A quickie Google didn't turn up anything, so I hauled down "La Technique." Pepin says "remove the sac (stomach) behind the eyes." Says it's full of gravel. Guess that's why it's often called a sand sac.

                  Thank you, Jacques. As always.

      2. I agree about the internal components needing to be left out of the broth. Another likely possibility:
        hot broths should not be covered...they need to cool down considerably before being covered and refrigerated. Covering hot chicken stock results in a sour brew that needs to be discarded...

        2 Replies
        1. re: penthouse pup

          "Covering hot chicken stock results in a sour brew that needs to be discarded..."
          I've never ran into this issue.

        2. Lobster stock should be made immediately, cooked briefly (<1 hour) and used shortly thereafter.

          I've made successful stock without removing anything from the lobster bodies. That being said, I've done better after removing gills/tomalley (a friend loves the tomalley spread on bread, so I save it for her).

          Perhaps the OP's bad luck was due to using the original boiling water from the lobsters.

          1 Reply
          1. re: shaogo

            The shells can be frozen and then used for broth if you do not have the ability to make the stock immediately or when running a restaurant and making a lobster stock for a shrimp or crab bisque. The frozen shells come completely cleaned and ready to make use when bought in bulk for this purpose.

          2. It is because Lobster stock should never be cooked past 40 minutes. Once you pass this point the lobster shells begin to break down and release contaminants into the stock making the stock gross and foul smelling. If you pull the stock from the heat after 35 minutes every time you should be fine. Chicken stock- no more than 4-5 hours and Beef- 8-9 hours or overnight. Beef bones do not tend to start breaking down like seafood and chicken do. It takes MUCH longer.

            1. I personally think that the water used to initially boil lobsters smells awful.

              1. I think lobster stock can smell a little funny while it's cooking, too. I don't really like the smell of shrimp shells when I saute them in oil (before making stock) either, but I do like the taste of the final product (of both).

                FWIW, I don't usually remove all the innards when I make lobster stock, either. I do keep the simmering time to under an hour when the shells are still in there (you can simmer it more to reduce it after you remove the solids, like you did). Adding a tablespoon or two of tomato paste (or a can of chopped tomatoes, etc) can help to counteract the grey color, which IME is totally normal.

                WRT to lobster cooking liquid, I usually save a cup or two of the stuff to use in the stock, but otherwise use fresh water for the rest of the liquid. The sludge in the bottom of your stockpot was probably goo from the original cooking liquid. We homebrew too and I know what you mean about the sediment - but it wasn't yeast in your broth :-) Oh and by the way - I wouldn't recommend that you use your brewpot to boil lobsters. I did that once when we were having a party - I needed a BIG pot! - and got into big trouble with the hubby b/c the lobster smell wouldn't come out of that pot, not matter how much I scrubbed. (I ended up buying him a new brew kettle so it worked out OK for him!).

                My favorite recipe for lobster broth is in Julia Child's The Way to Cook. Look at the recipe for Lobster Americaine - I use that as a guideline (since i'm usually using the shells leftover from a lobster dinner). Usually I stop at the stock/broth stage and freeze it to make soup, rissotto, etc at a later date, but once or twice I've gone all the way, reduced the stock and make the thickened sauce. It's AWESOME over a poached egg, perched on top of a toasted English muffin.

                1. i also think you've cooked it too long. i find shrimp and lobster stocks made from the shells become bitter when over boiled.

                  1. I work in a seafood restaurant and we happen to make a lobster stock there. Since we have to make so much we just bulk order lobster tail shells and use those, but for the first week or so we would use heads as well.

                    Anyways, we don't use the same water as the lobster had initially cooked in. You could probably think and find a couple different reasons for this, but I always just figured that it's water that has been filled with whatever a live lobster was carrying- be it sand from wherever, bacteria, parasites etc. In theory only the sand would be an issue and it should be fine to use the water, but just to be safe I'd (personally) veer away from it.

                    We also actually keep the stock on heat for quite a while (sometimes because people forget, tbh) sometimes 2 hrs (barely a simmer though) and it's still fine. But the most important thing I've found with shellfish and/or fish stocks is the cooling. As soon as you're done with it you have to cool it down right away and as fast as possible. Just putting the hot liquid into the fridge (especially covered) will make it a playground for bacteria. After four hours like that it’d be questionable, but more than a day and I wouldn’t want to touch it myself. Plus, putting something hot in your fridge puts the whole space at risk since it’s heating everything else up as well.

                    Best bet: toss it in an ice bath, then once it's lukewarm put it in your fridge (no lid until it's cold- you couldn't get away with this in a restaurant, but with a home kitchen you should be fine).

                    As for the reducing, that probably didn't help the smell any- especially if you had a pretty potent stock to begin with. But I don't really think that would be the only cause. I'm not going to say "you shouldn't reduce a stock" because that's not true; I just don't really think it's really necessary unless you're adding other ingredients to it and making a sauce (like a lobster veloute).

                    And btw, the sediment and colour are completely normal.
                    The colour can be avoided by removing any green or black organs; or changed by using tomato puree/paste/other tomato product. Our lobster stock is actually a dark brown.

                    The sediment is just some proteins from the lobster coagulating. This happens in all meat stocks. If you want to get rid of it you could probably try using a clearmeat to filter it that way (I've never tried this on a lobo stock, but I imagine it'd work the same way as with veal or beef).

                    To make a clearmeat, mix together an egg white with some veg (small rough dice, maybe 1cm ish) like fennel, carrots, onions, celery etc (typical stock mirepoix with anything else that won't colour it) and raw ground beef. You can add aromatic herbs if you want, but it's not necessary. The idea here is that the egg white should hold together the other ingredients and you'll have a bit of a hamburger patty-like paste.

                    To use it, initially heat the clearmeat with a little bit of the stock- stir it frequently and keep it on low heat. Once the meat has lost it's "raw colour" add the rest of your stock. Stir it a lot- this is important since you need the lobo protiens to stick to the egg white and ground beef. Bring it to a boil. You can stir it until it gets to a hard simmer, then let the clearmeat settle at the top (it should float). We call this a "raft". Once it boils, turn the heat down to low and break a small hole in the raft so that the stock can circulate through it (but not carry the clearmeat throughout). Keep it on low for maybe 20 mins, then strain off the raft when there is little to no water movement. If you pass it through cheesecloth after that you should end up with a perfectly clear lobster stock (though now some might consider it a consomme).

                    Sorry that was so long. ._. I'm not a super concise person.
                    Hopefully it helps anyone else who happens along this post.


                    TLDR VERSION:
                    At any rate, it just sounds like the smell could have come from a combination of:
                    -not removing the brain/sac/whatever else you want to call that thing between the eyes (I've also heard about this and have been told to only ever remove that)
                    -Improper cooling
                    -Use of the original cooking liquid (but really, this should probably be fine for home cooking)

                    The sediment and colour is completely normal.


                    1. Don't use the original water.
                      Always carefully clean the shells
                      Don't ever 'boil' the stock........even as the water is brought up to a simmer
                      Celery will always add a bitter note to any stock
                      Only simmer a fish stock for a short time.....the longer the simmer the more bitterness comes out of any shellfish
                      (Aside) The very best primary dashi is made by soaking the dried bonito flakes for only a few seconds)
                      Protein strands/salts and minerals in all seafood seem to be very affected by overexposure to heat.
                      'Lao Tzu' offered: "Governments should behave as one would cook a fish. Very delicately".