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Fruit Caviar: How Do They Do It?

On another, Boston, thread we started talking about these amazing 'fruit caviar' bubbles that are a topping option for a number of frozen yoghurt shops. Luther referred to them as
"alginate/calcium reagents used to make the "fruit caviar" topping". Can anyone explain in layman's terms how these bubbles work?( I am absolutely chemistry-challenged but am fascinated by these things.) Thanks much!

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  1. Thats kind of the simplest explanation you can give for it. You mix sodium alginate into fruit juice and then drop it into a calcium chloride solution and it creates the spheres. The scientific reason as to why it happens is far more complicated.

    http://www.youtube.com/watch?v=LDIsfQ...

      1. re: Luther

        His recipe collection with many "modern" recipes including "fruit caviar" is also highly recommended:

        http://cdn.khymos.org/wp-content/2009...

      2. Alginate is a seaweed-based thickener. In a ph-appropriate mixture (slightly acidic) the alginate-juice mixture reacts with the calcium chloride bath to create a gel. Depending on the size of the drops and the length of time it sits in the bath the drop can either be liquid inside or gel all the way through.

        1. If this interests you there's a wonderful series of video lectures by a number of chefs who visited Harvard last year to explain the science behind their methodology:

          http://itunes.apple.com/itunes-u/scie...

          #8 is directly on-topic but they are all fascinating.

          4 Replies
          1. re: ferret

            Thanks for this great link! LOVE things like this. Now if only my copies of modernist cuisine would arrive ><

            1. re: ferret

              man o man, ferret, you are one HOT TICKET!

              And all of you, what very helpful explanations; I am really delighted to learn about this! thanks so much.

              p.s. do yall have any idea when and where these fruit caviar were invented ?

              1. re: opinionatedchef

                The series is very entertaining. The first 10-15 minutes covers the scientific principles and can be skipped if you like. For me, the second episode with Joan Roca was exceptionally good, despite the poor translator. Hats off to Harvard for putting together such a great series.

              2. re: ferret

                Thank you for posting this! What a great resource.

              3. Maybe they buy it: http://www.fruitcaviar.de/

                There is another, perhaps more accessible method which uses agar agar as the thickener, and the caviar mixture is dropped into chilled oil. Agar has a high melting point, so spherifies quickly once in the cold oil. Agar caviar is solid rather than potentially liquid inside like the alginate version.

                5 Replies
                1. re: babette feasts

                  well, that is pretty darn fun! thanks much for the link. there must be a U.S. producer too because the flavors i've seen in CA and here in MA are not this german producer's flavors. Gonna seek further!

                  1. re: babette feasts

                    making fruit caviar is actually VERY easy, All you need is a digital scale, a syringe and the chemicals which can be bought from amazon.

                    1. re: twyst

                      what great news! maybe i could find some chemistry inclined friends and have a fruit caviar making party!

                        1. re: ferret

                          TOOOOOO much!!!!!! if i order, are you comin over to play? : - )
                          <jumping up and down like 5 year old>