Processed Food without Hechsher: Is It Kosher?
 
If a processed food does not have supervision/hashgacha, here are some issues to consider:

• Ingredients;
• Utensils/processing equipment;
• Bishul akum/“prestigious” foods that require Jewish involvement in the cooking;
• Heating system (recirculated steam?);
• Heter for milk without being supervised - which conditions and countries can be relied on;
• Non-food ingredients (lubricants, preservatives, emulsifiers...);
• Reliability of the producer;
• Is the non-kosher ingredient batel/nullified?
  • ownership (Is the food's producer or owner Jewish?)
  • intended consumer (Is the food being produced specifically for Jews, or is it for the public and Jews are some of the customers)?
  • Was the non-kosher substance added intentionally?
  • Does the non-kosher substance have flavor?
  • Was the non-kosher substance added for flavor?

A hechsher/kosher supervision is not needed on:

• Beer made in the US (and sometimes in other countries).
• Nuts (dry roasted) without additives.
• Olives--assumed to be kosher unless mixed with ingredients that may be non-kosher, such as:
  • Vinegar (sometimes made from grapes).
  • Non-kosher chemical preservatives (in commercially sold olives).
  Note In open markets in which olives are sold in bulk, you may eat olives after checking the ingredients.
• Olive oil (extra virgin).
• Pure fruit juice NOT made from concentrate (such as orange or pineapple juice) does not normally require a hechsher (except for grape juice, which always requires a hechsher!).
  Note Juices from concentrate might have kashrut problems due to the vats in which they are cooked or pasteurized. If you can verify how the juice was processed and that there are no kashrut problems, you may use the juice without a hechsher. There may also be problems with juice made from fruit or vegetables which were grown in Eretz Yisrael, due to orla, shmitta, teruma and maaser.
• Scotch whiskey--even where it might have been aged in sherry casks.
  Reason Any sherry would be nullified as less than 1/6th. 
  Note Other types of whiskey may not be kosher because:

  • Glycerine may have been added;
  • The whiskey may have been owned by a Jew during Passover in a previous year; or
  • Milk, or alcohol derived from milk, might have been added.
• Sugar (confectioner's) needs kosher supervision only for Passover. Regular sugar never needs kosher supervision (currently).
• Unprocessed foods such as
  • Raw fruits and vegetables (but might need to be checked for insects), and
  • Water, but some unfiltered tap water might have tiny creatures in it which make the water non-kosher.

 

Jewish Festivals are listed in the Torah and are of two types: 

1. Three pilgrimage festivals (shalosh regalim):

• Passover,
• Shavuot, and
• Sukkot (including Shimini Atzeret).

These festivals were celebrated in ancient times by "appearing before God"--by bringing offerings to the Tabernacle or Temple.

2. High Holidays: 

• The Jewish New Year (Rosh Hashana—“Yom Teru'a” in the Torah), and the
• Day of Atonement (Yom Kippur).

 
Duration
Jewish holidays that were originally one day are now observed as follows:

• Rosh Hashana--2 days.
• Yom Kippur--1 day.
• Shavuot--1 day in Eretz Yisrael or 2 days elsewhere.
• Passover has festival days at the beginning and end of the holiday and intermediary days of lesser holiness, which are called chol ha'moed. In Eretz Yisrael, Passover lasts for 7 days in total and the first and last days are festival days. Outside of Eretz Yisrael, Passover lasts 8 days and has two festival days at the beginning and two at the end.
• Sukkot has festival days at the beginning and at the end and intermediary days of lesser holiness, which are called chol ha'moed. In Eretz Yisrael, Sukkot lasts for 8 days and the first and last days are festival days (the last day is Shimini Atzeret). Outside of Eretz Yisrael, Sukkot lasts for 9 days and the first two days and last days are festival days (the 8th day is Shimini Atzeret and the 9th day is Simchat Torah).

Character
Each holiday contributes its own character to Jewish life (Passover--the theme of freedom; Yom Kippur brings atonement, etc.). 

Celebrating
How to celebrate these holidays is detailed in our Oral Law and halacha books. Jewish festivals as practiced today are similar in holiness to Shabbat. As with Shabbat, the Jewish festival has candle lighting, kiddush at two meals, and havdala.   We eat our best food and wear our best clothing on Jewish festivals (we eat our next-best food and wear our next-best clothing on Shabbat!).
The main idea behind eating meals on Jewish festivals is joy (simcha), so you should drink wine and eat meat (only if you enjoy wine and meat).  There is no third meal on Jewish festivals since people used to eat two meals each day (adding a third meal on Shabbat was for enjoyment/oneg).
 
Melachot
Any activities or actions permitted on Shabbat are also permitted on the Jewish festivals. Actions that are forbidden on Shabbat are generally also forbidden on Jewish festivals, but there are some leniencies (only if the actions are needed for that festival day).
Examples

• Lighting from an existing flame,
• Cooking and baking for the Jewish festival day, and
• Carrying outside the eruv (hotza'a--transferring objects between domains).

 
Grama
Grama (indirectly causing an action) is permitted on Jewish festivals (but not on Shabbat). For example, you may advance or delay a timer that will make a light go on or off in the future (the timer must already be plugged in and operating from before sunset of the festival day).
Note For an action to be considered indirect based on time, there must be at least 2.5 seconds after the first action is done before the resulting action begins to happen.

Psik Reisha Dla Neicha Lei
Psik reisha dla neicha lei is forbidden on Jewish festivals, just as it is on Shabbat.

D'oraita Restrictions
D'oraita restrictions apply world-wide to:

• First and seventh days of Passover,
• First and eighth days of Sukkot,
• First day of Shavuot,
• Yom Kippur,
• First day of Rosh Hashana.

Note The same restrictions apply to all other Jewish festival days but are rabbinical.
 
Women
In general, women are not required to perform the positive, time-dependent commandments. Women and girls are not required to eat any Jewish festival meals except the Passover seder meal (but they are not allowed to fast on those days).

Men are required to hear at least 60 shofar blasts on Rosh Hashana (l'chatchila) in order to fulfill the commandment of hearing shofar:  30 before the musaf amida and 30 afterward.  But they fulfill their requirement (b'di'avad) if they have heard at least 30 on each day of Rosh Hashana. 
Women only need to hear 30 shofar blasts on each day of Rosh Hashana.