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Nov 15, 2011 05:23 PM

Why do my cookies crack on top?

I am baking biscotti, and having some trouble... and yes, I've tried using the search feature already.
The cookie logs are cracking along the tops, deeply enough that when I slice the logs into biscuits, the slices are breaking or crumbling badly. Do I need to use a higher gluten flour, or mix a little longer?

250 gm butter
300 gm sugar
800 gm AP flour
100 gm cocoa powder
330 gm eggs
30 gm water
misc. amounts of vanilla and spices
100 gm chopped dried fruit
30 gm baking powder (about).... I measured 3 tbsp

first bake is 325ºF convection for 20 min
2nd bake is 315ºF convection for 15 min

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  1. I use the stupid cups and spoons, so I don't know how to read the grams thing -- although I know it is the better method. It sounds to me that there may be too much sugar or too much butter. Both of which can cause the baked goods too fragile and too crispy.

    1. Not sure, but I have found that some biscotti logs cut much more neatly if wrapped after the first bake and allowed to rest overnight. The moisture evens out and they get softer.

      In American...
      2 sticks butter plus a pat
      1-1/2 cups sugar
      about 5-1/2 c flour
      about 1 c cocoa
      6 eggs
      1 oz water
      4 oz dried fruit
      1 oz baking powder/3TB

      You could try less baking powder, 2TB should be enough to get a decent rise, and if they are a little dense it's OK in my book. I don't think it's too much butter or sugar. Is the dough pretty stiff or wet and sticky?

      1. I use a biscotti recipe that calls for no butter or oil. Just eggs to keep it together.

        1. I have many biscotti recipes in my file, some use butter, but the more traditional recipes use baking powder and eggs senza butter. That's neither here nor there.

          The ratio of one egg per cup of flour is traditional, two eggs will give you a softer biscotti that is more crumbly. You don't need a higher gluten flour. I concur with babette feast, cut back on the baking powder, 2-2 1/2 Tbsp will be plenty.

          Here's Michael Ruhlman's ratio for biscotti, compare your recipe, which is about 4X his, to check your butter/sugar/flour/egg totals:

          I give my biscotti at least 20-30 minutes rest after the first bake, before I slice. Are you using a serrated bread knife for slicing?

          1. Thank you for your responses and thoughtful questions.
            * Typically, I may wait anywhere from 1 hr to overnight between the first and second bakes. There seems to be no difference in the slicing.
            * I've used both serrated and non-serrated knives for slicing, with no discernible difference.
            * The quantity/weight of sugar is about 1/3 less than the original recipe published in a popular magazine.
            * Dough is moderately wet; not as liquid as muffin batter, but not as stiff as "rolled cookies"... maybe the texture/moisture of a drop cookie.
            * My main concern is about the deep cracking during the first bake. My secondary concern is the delicate texture.

            I'm going to try another batch, and bake at a slightly higher oven temp.
            To be honest, I've used the same recipe (I think) for years, with nary a problem. I sell the biscotti during the holiday season, as a gift item. The cracking issue began when I got a new oven, with a slightly different fan configuration.
            Thank you all again for your input. Should you have further suggestions, I'd love to hear.

            9 Replies
            1. re: KarenDW

              New oven eh? Did you check the oven temp? That could be it in a nutshell, with the different fan config.

              The texture of the dough sounds right. How long have you been using the recipe with the reduced amount of sugar? Less sugar could result in a more delicate texture.

              No other changes, aside from your oven? Different flour brand? Just food for thought.

              1. re: KarenDW

                Oh new oven huh? I also reread your post above again. Did you say you use a convection oven? Was your previous oven a convection oven? There can be a big difference between a convention oven vs a convection oven when at the same temperature. I don't think less sugar should be the problem. In my expereince, more sugar makes the pastry/cookie more crispy and easier to crumble.

                1. re: KarenDW

                  It sounds like a crust is forming before the interior dough is finished expanding, resulting in cracks. My guess is that the convection fans in your new oven are drying out the surface of the logs quicker than your old oven did. If you can turn the fans off you might want to try doing the first bake in conventional mode, possibly at a slightly higher temperature. If the fans can't be turned off you could try scoring the raw dough logs at the locations you'll be slicing them in to biscuits to try and control the cracking.

                  1. re: KarenDW

                    goes to look for oven thermometer...

                    1. re: KarenDW

                      I agree with Coogles. It may go deeper than just the thermometer issue. it is an issue of convection vs traditional radiative heating. There is some general rule for converting traditional radiative oven heating to convection oven heating.


                      (this is just a rule of thumb conversion, you will have to fine tune it).

                      1. re: Chemicalkinetics

                        I agree with Coogles also, for the reasons Chem mentioned.

                        For the OP-Try Coogles technique, turning the fan off, or just turn the temp down.

                        Rule of thumb (mine) for convection is 25° lower than recipe temp. Chem's link states 50° lower for baked goods, but that's not across the board, and you will have to play with it a bit.

                        Cool link, btw, chem!

                        1. re: bushwickgirl

                          I have no idea if the link is useful. I actually tried to play with the link, and notice it just minus 50oF for all temperature. It does not make sense how 600oF is convert to 550oF, while 100oF is convert to 50oF. Really? 100oF convert to 50oF (lower than room temperature)!?


                          It is probably not a bad idea if the OP can turn the fan off (convection off). If this solves the problem, then we know the cause is not the recipe, and that the OP only have to fine tune the oven setting -- and not the recipe.

                          *Edit: what happened to your vomiting pumpkin? :D *

                          1. re: Chemicalkinetics

                            Hehe, he slunk back to the p-patch, after overdoing it at a Halloween party. ;-D

                        2. re: Chemicalkinetics

                          I've always used a convection oven. But the current oven is a different manufacturer than the previous. Can't find the oven thermometer :(