Esrog Jam

Leib from Har Nof asks:

My wife made esrog jam out of kedushas shvi’is
. Do we have to perform bi’ur on this jam and if so, when?

There is a difference of opinion as to whether the esrog
requires bi’ur at all. Some hold that since it remains on the tree from
year to year (hadar b’ilono mi’shono leshono), no bi’ur is
required. Only if there is “nothing left for wild animals” in the field is
there a requirement to do bi’ur. The Chazon Ish [13:22] writes
that even if nothing is left on the tree, one is exempt from bi’ur as
long as there is still fruit on the ground. Others are of the opinion that esrogim
are liable for bi’ur. However, not all agree as to the appropriate time
for fulfilling this obligation. Some hold that the 15th Shevat
is the time for bi’ur. Others hold that one must declare the esrogim
(ownerless) immediately after Sukkos. The logic behind the
opinion placing the obligation after Sukkos is that nowadays an esrog
orchard is completely stripped of its produce – including what lies on the
ground – before Sukkos. Perhaps there might be another kosher esrog
out there! Therefore, in order to take account of all opinions, one should
declare esrogim hefker immediately after Sukkos, but not
reacquire them till after the 15th of Shevat. How many esrogim
does one need to have in one’s possession in order to be liable for bi’ur? The Poskim
(halachic authorities) hold that half an esrog constitutes one portion of
dessert, eaten at a single meal. Accordingly, if one does not have more than
one-and-a-half esrogim (three meals) per member of one’s household, one
would not be liable for bi’ur. If your jam contains more than this
amount, follow the instructions above.