Commemorative loaf of french bread

Susan Blakney <susan [at] westlakeconservators__com> writes

>How can one preserve a magnificently sculpted/decorated country
>French loaf (round, about 2.2 kilos, composed of almost-whole
>wheat--French type 110--, water, salt, and a natural leaven, known
>to some as sour dough). It was fashioned in France to commemorate a
>grand occasion here in Ithaca, NY and we would like to preserve it
>beyond the natural "staling" life of the loaf. Can it be varnished,
>stained or otherwise treated? Given our lack of dexterity and
>experience, we need sage advice and a simple solution.

I've had success with the following method with various ethnic
breads that I've prepared for exhibit and program use.  The key
thing is to remove as much of the water content as possible.  This
method does require lab equipment, so it's not quite simple, but I
consider it more effective in the long term than surface spraying
with Krylon.

    Weigh the bread.

    Slowly dry in a lab oven (if available).  I've found that 100
    deg. F works well.  Take the bread out once a day and re-weigh.
    Once the weight levels off, the drying is done.  You can also
    calculate the EMC for future reference.

    The bread will begin to regain moisture if the RH in the room is
    high, so don't let it be exposed too long before the next step.

    Prepare a consolidation solution of 3% w/v Paraloid B-72 in
    acetone in a volume sufficient to fully immerse the bread.
    Place the bread in a stainless steel pan or cylinder and pour in
    the solution.  The solvent may extract some color, but that
    should be minimal with this type of bread.  That usually happens
    when eggs were used in the recipe.

    Place the container in a vacuum chamber, seal, and turn on the
    pump. Evacuate to 25 mmHg and allow for complete penetration of
    the consolidant which is indicated by a cessation of bubbling.

    Remove the bread from the container and allow the excess  liquid
    to drain.  Place the bread on a stainless steel rack inside a
    fume hood and dry with the hood on for at least a week, or until
    the solvent/consolidant odor is minimal.  Any surface gloss can
    be reduced with acetone.

Let me know if there are any questions.

Paul Storch
Objects Conservator
St. Paul, MN


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                  Conservation DistList Instance 24:30
                 Distributed: Sunday, December 19, 2010
                       Message Id: cdl-24-30-010
                                  ***