Rabbinic guidance is recommended when using a river, lake, or spring as a mikva due to:

• Problems of mud, dirt, or sand, and
• Difficulty in checking if the person is fully underwater,
• It might not be a kosher mikva.

Although the mitzva d'oraita is to thank God only when you are satiated from the meal, chazal decreed that we say birkat ha'mazon even when eating only the volume of a k'zayit and even if not satiated. So you must still say birkat ha'mazon after eating at least 1.3 fl. oz. (39 ml, or 1/6 cup) of bread within four minutes--even if you are not full.  This is known as birkat ha'mazon d'rabanan.

Food Nullification in Utensils: Torah-Law and Rabbinic Decree
By Torah law (d'oraita), any clean utensil, countertop, etc., automatically reverts to neutral/pareve and kosher after not being heated to more than 120° F (49° C) for 24 hours.
But by rabbinic decree, utensils do not automatically become neutral/pareve even after 24 hours and must be kashered by heat (libun—direct heat; hag'ala—boiling in a pot; or eruy rotchim—pouring boiling water over item) or, if some types of glass, by soaking in water (meluy v'eruy ).
 
Changing Gender of Utensil
You may kasher a pot or cooking/eating utensil from:

• Non-kosher to kosher, or
• Year-round use (chametz) to kosher for Passover.

 
You may not intentionally kasher a utensil in order to change it from dairy to meat or meat to dairy; you must first kasher it from accidentally (or intentionally) non-kosher to kosher/pareve, or from non-Passover to Passover/pareve. You may then use it for either dairy or meat.

Once you have used it for that gender, the item retains that gender (unless you re-kasher it for Passover or you make it non-kosher first, then kasher it to neutral/pareve).
But if you accidentally heat meat with a dairy utensil or vice versa, you may kasher it back to its original gender by any one of the kashering methods, depending on how it became non-kosher.
 
Items/Materials that Can Be Kashered
The following materials can be kashered:

• Glass, including Corelle, if not used directly on the stove or oven. Glass does not change gender or other kosher status unless heated on a flame or in the oven. Unless it is heated in this way, glass does not ever need to be kashered (except for Passover) (see Meluy v'Eruy, below).Glass, including Corelle, if not used directly on the stove or oven. Glass does not change gender or other kosher status unless heated on a flame or in the oven. Unless it is heated in this way, glass does not ever need to be kashered (except for Passover) (see Meluy v'Eruy, below).Glass, including Corelle, if not used directly on the stove or oven. Glass does not change gender or other kosher status unless heated on a flame or in the oven. Unless it is heated in this way, glass does not ever need to be kashered (except for Passover) (see Meluy v'Eruy, below).

• Granite (not granite composite)
• Marble
• Wood, if smooth (see notes on Eruy Rotchim, below)
• Metal, including stainless steel, cast iron, and aluminum.

Note While metal can be kashered if thoroughly cleaned, welded handles and other difficult-to-clean parts may render a metal utensil not kasherable. You might be able to use libun kal on the problematic area and still use hag'ala for the remainder of the utensil.
 
Items/Materials that Cannot Be Kashered

• China
• Corian
• Corningware
• Crockpot
• Formica
• Glass that has been used directly (kli rishon) on a stove or in an oven; however it can be kashered in a kiln
• Granite (composite)
• Knives with Plastic Handles (knives with wooden handles may be kashered if there are no cracks in the wood and if the rivets do not have spaces that catch food and prevent you from cleaning it completely)
• Mixer-there might be exceptions. Consult a rabbi.
• Plastic
• Porcelain (Enamel)
• Pyrex (if used directly on stove or in oven--kli rishon)
• Rubber (synthetic)
• Silestone
• Silverstone
• Stoneware
• Teflon
• Toaster/Toaster Oven
• Waffle Iron.

 
Pot Lid Handle
Kashering
The handle on a pot lid does not need to be kashered for normal use during the year. 
Reason It does not normally get hot.
Cleaning
However, the pot lid handle must be removed and the lid cleaned where the handle attaches, if possible.
Note If the gap between the handle and lid cannot be completely cleaned, you may not use that lid for Passover and you normally may not kasher it if it becomes non-kosher. If the lid handle cannot be removed, consult a rabbi.

Pot or Pan Handle
A plastic handle that gets hot, especially if it is over a flame on a burner, may not be kashered. If the handle becomes non-kosher, it must be replaced. If a plastic handle connects directly to the metal of the utensil, consult a rabbi about what to do.
 
Food Nullification: Heat-Kashering
Three Methods of Heat-Kashering
Heat-Kashering is of three types:  Libun, Hag'ala, and Eruy Rotchim.

1. Libun (Direct Heat)
   How It Works  Burns up any residual food taste

       

• Direct a flame, such as a blowtorch, onto the inside of a pot. Pot is hot enough when a piece of paper that touches the outside of the utensil burns (it does not need to burst into flame, just to smolder), or
• Put the pot into the oven at 500 ° F for 40 minutes. (First, remove any non-metal handles; they will need to be kashered separately or not used.)

   

2. Hag'ala (Boiling)
    

• Boil Method Boiling water within the pot to be kashered, and making the boiling water overflow, or
• Dip Method Dipping a smaller pot or utensil to be kashered into a larger pot of boiling water.

       

• If the pot in which you are kashering the items had been heated to 120° F (49° C), with food of that gender in the pot, or more within the previous 24 hours, the items you are kashering will assume the gender of the pot.
• If the pot in which you are kashering the items had NOT been heated to 120° F or more for at least 24 hours, any items that are kashered in it will become kosher and pareve.

     
 

3. Eruy Rotchim (Hot-Water Pour)

         

 
Food Nullification: Meluy V'Eruy
Meluy V'Eruy To Kasher Glass
Halachically, “glass” includes Arcoroc, Corelle, crystal, Duralex, and Pyrex.
NOTE In pre-war Europe, where glass was expensive and hard to obtain, it was customary to kasher drinking glasses, especially for Passover, by soaking the glasses for three 24-hour periods (meluy v'eruy), as follows:
Step 1: Submerge glasses in cold water for 24 hours.
Step 2: Empty water, refill, and submerge glasses again.
Step 3: Repeat Step 2.
NOTE If any of these materials were heated directly on a flame or other heat source, they cannot be kashered by meluy v'eruy!

Three Shabbat Meals
We are required to eat three Shabbat meals, as a rabbinic (d'rabanan) enactment to enjoy Shabbat (oneg Shabbat). The first Shabbat meal must be at night and the remaining two must be during the day (the third meal must be eaten after halachic midday). Friday night dinner and the first meal on Saturday are preceded by kiddush. For the first two Shabbat meals, say ha'motzi over two complete loaves of bread, each of which is at least 1.3 fl. oz. in volume. For the third meal, the ideal is to use two complete loaves of bread, but the requirement of eating the third meal can also be fulfilled by eating any food other than salt or water.

Source of Saying Shabbat Kiddush

• Saying kiddush on Shabbat night is a commandment from the Torah (d'oraita).
• Saying kiddush on Saturday morning is a rabbinical (d'rabanan) enactment.

Note If you did not say Friday night kiddush, you must say that version of kiddush on Shabbat morning and it is then a requirement from the Torah (d'oraita). Do not begin with va'yechulu; instead, begin with borei pri ha'gafen and say the second blessing of kiddush.

Source of Kiddush Location
Saying kiddush at the place where you will eat your meal is a rabbinical (d'rabanan) enactment.

Shabbat Kiddush-Meal Quantities: Evening

• For evening kiddush, a minimum of 4 fl. oz. (119 ml) of wine must be blessed on and at least half must be drunk.
• For the evening meal, as on Shabbat lunch and all required Jewish festival meals, a minimum of 1.9 fl. oz. of bread must be eaten within four minutes.

Shabbat Kiddush-Meal Quantities: First Meal on Saturday
Shabbat day first meal has two separate eating requirements.  They may be combined (say/hear kiddush and start the main meal right away) but are often done separately (say/hear kiddush and then eat some mezonot; the main meal is eaten later in the day).
Note Since eating and drinking requirements on all morning kiddushes (both Shabbat and Jewish festivals) are d'rabanan, the required beverage amount for morning kiddush is only 3.3 fl. oz. (99 ml) instead of the d'oraita 4 fl. oz. (119 ml), which is required for kiddushes for Shabbat evening.
1) Morning kiddush requires a halachically legal “meal” with these elements:
      a) Blessing on a minimum of 3.3 fl. oz. (99 ml) of wine (or other beverage),
      b) Someone's drinking at least 2 fl. oz. of the beverage, followed by
      c) Eating at least 1.3 fl. oz. (39 ml, or 1/6 cup) of some type of mezonot (or bread) within four minutes.
Note If you drink at least 3.3 fl. oz. (99 ml) of wine within 30 seconds, you do not need to eat mezonot.
Note You do not need to drink the wine or other kiddush beverage to fulfill “establishing a meal.” You may hear kiddush and then simply eat the required amount of bread or mezonot. This applies to Shabbat or Jewish festivals, evening or morning.
The kiddush “meal” does not have to satiate.
Note If you have not fulfilled the requirements for kiddush, you may not eat other foods, such as fruit or fish at a kiddush.

2) The real meal (kovei'a se'uda) of Shabbat lunch requires eating at least 1.9 fl. oz. (56 ml) of bread (or matza during Passover!) within four minutes. It should include enough food to satiate.
Note You can simultaneously fulfill the requirement to “establish a meal” and to “eat a meal” by eating one (the same) piece of bread.
For details on fulfilling the first two meals' requirements, see Shabbat: Kiddush.

Shabbat: Eating a Meal Requirement: Third Meal
For details on fulfilling the third meal's requirements, see Shabbat: Third Meal (Se'uda Shlishit).

You must give 10\% of your net, after-tax income or received gifts of money to charity (ma'aser kesafim), by rabbinic enactment. For what is considered income, see Charity/Tzedaka: On What To Give.

We are stringent in applying laws if we are uncertain about Torah commandments.
We are lenient in applying laws if we are uncertain about rabbinic commandments.
 

The only type of laws that may sometimes be overridden to help with shalom bayit (promoting peaceful family relations) or kibud av va'eim (honoring parents) is rabbinic law, not Torah law. A rabbi should be consulted in these cases.

A business whose sole or major owner is Jewish may not be operated on Jewish festivals (and Shabbat), even by non-Jewish employees. There may be possibilities to allow operation by relinquishing majority control, but the issues are complex and rabbinic guidance is essential.

A business whose sole or major owner is Jewish may not be operated on Shabbat (and Jewish festivals), even by non-Jewish employees.

A non-kosher substance becomes kosher once it is modified and no longer has the original taste.

Here is the order for blessing over the Shabbat candles by women:

• Light the candles,
• Put your hands in front of your eyes (this a universal custom), and
• Say the blessing lehadlik ner shel Shabbat.

Plants grown off the ground or inside a house are also not subject to shmita.

 

1. What Makes a Woman a Nida

 
Introduction to What Makes a Woman a Nida
Vaginal Blood Flow
Only vaginal blood flow makes a woman nida. 
 
Nida D'Oraita
According to Torah law (d'oraita), a woman becomes a nida when she experiences a flow of uterine blood, preceded or accompanied by a hargasha. Because uterine blood flow is difficult to distinguish from the more general vaginal blood flow, we assume that a vaginal blood flow is from the uterus--unless a medical person (it could be a midwife) determines that the blood flow is not uterine.
 
Nida D'Rabanan
 
By rabbinic law (d'rabanan), a woman can become a nida even with only a qualifying stain (see below).

Hargasha
A hargasha is anything that signals that the woman's period is imminent. There are three classical hargashot, as well as possible hargashot that pertain only to an individual woman.
Note Many women today do not have hargashot.
 
Classical Hargashot
There are three classical hargashot:
1) Body Tremor
2) Petichat HaMakor
Some women, at petichat ha'makor (“opening of the uterus”), have a sensation of release similar to when one's bladder opens to urinate.
3) Zivat Davar Lach
Sensation of wet discharge that comes only with her period; this is not the wet discharge that every woman normally feels multiple times daily.
Note She does not necessarily need to feel it coming from her cervix in order for it to make her a nida.
 
Individual Hargashot
What Is an Individual Hargasha
The individual hargasha can be any physiological occurrence (pimples on her face, a bout of yawning, a bloated feeling in the belly, etc.) that correlates with a woman's getting her period within 24 hours. To become established as a hargasha, it must have happened three times in a row.
 
Note Cramps for most women may be a hargasha, since they may mean that the woman is about to have her period.
 
When a woman has a hargasha, we assume that her period has started, and she should immediately stop what she is doing and check internally with a bedika cloth. If she does a bedika as soon as possible and the cloth shows a forbidden color, or shows no discharge at all, she immediately becomes nida for at least 12 days, after which she goes to the mikva. 
Note If she had a hargasha and finds no blood and no discharge, she becomes a nida, since we assume there was blood and she just didn't find it.  If the bedika cloth shows brown, magenta, salmon, brick, amber, orange, etc., the rabbi will want to see the cloth to determine her status.
Note Most medium browns are OK.
 
What To Do If Not Sure
If she is not sure she has had a hargasha, she asks a rabbi and together they will sort out the answer.
 
 
Nida D'Rabanan
 
Stain (without Hargasha)
 
Stain Colors
A rabbi should be consulted in all matters of questionable colors of stains.  Some may seem to you to be forbidden but turn out to be permissible, and vice versa.
 
Stain Location
A stain of a color that could make a woman a nida can be on material or on the woman's body. None of the following lenient conditions apply if the woman is nida d'oraita:
   

1. Not positively attributable to another cause, AND
2. At least the size of a gris. For small, unconnected spots, she must evaluate whether, together, they equal the size of a gris (on material, the spots DO NOT get combined). If yes, she should consult a rabbi.

 
 
II. HARCHAKOT: How Do the Couple Conduct Themselves while the Wife is a Nida?
 
According to Torah law, when a woman is a nida, she and her husband are prohibited not only from having intercourse, but also (“lo tikrav”—Vayikra 18:19) from having any physical contact of a passionate or romantic nature (negiya shel chibuk v'nishuk)--those patterns of physical contact that often lead to intercourse. Since the penalty for violation is kareit, husband and wife should live separately during the nida period, but because we don't, we use “distancers” (harchakot) as reminders of distance while living together in the same home. The harchakot sensitize us to the smallest gestures of love. The couple who know that in a finite amount of time their union will not only be permitted, but even be davar sh'bekedusha--a thing of sanctity--will have the willpower to wait it out.
 
These harchakot are applied during the nida period:
                                 
III. Tahara after Nida:    

1. Wash or cleanse lower regions of the body.
2. Do an internal check/bedika: Insert a white cloth into vagina and circle it around to make sure to get every nook and cranny.
3. Moch dachuk: Insert a bedika cloth within two halachic hours of sunset and leave it in until after dark.

 

1. Bedika

 

2. White Underpants

 

3. No Hesech Da'at

A woman does not need to think about the seven clean days all of the time, but she must keep in mind, during the entire nida purification process, that she is not in an active nida state.  
Situation A woman found a stain and asked a rabbi about it. She assumed she was definitely nida.
What To Do Once she assumes that she has become a nida during that seven-day period, she must begin her count again--even once she has found out that she was not, in fact, a nida. 
Note If she asked the rabbi while not yet assuming that she was definitely a nida, she may continue her original count after the rabbi determines that she was not a nida.

• Full body cast.
• Being covered with sand.
• Being sweaty from head to toe.

• Moisturizer that covers most of her body.
• Adhesive that is left on her skin after a band-aid has been removed.
• Imperfect manicure, if she would not go to an interview like that.

         
 

• Shalom Bayit (in this case, she is not permitted see her husband until after dark Friday night).
• Dangerous Neighborhood.
• Infertility Issues (if she will miss ovulation if she does not go Friday night).

    Kosher immersion/tevila requires simultaneous immersion of every exposed part of the body (not bet ha'starim).   Here is the best way to accomplish simultaneous immersion:

• Enter the water until it is about 12 inches above the navel. 
• Make sure that every part of your body is relaxed (if you squeeze anything, you create crevices and cracks that impede complete access to your skin). 
• “Flesh”/basar is exposed to the water when standing while leaning a little forward.
• Exhale and push yourself under the water until you are certain that all of your body and all of your hair are submerged. 
• Once your head is above the surface of the water, say the blessing and then immerse again, the same way.

 
IV. Anticipating the Next Period/Veset
 
What To Anticipate
In anticipating the time of the month when her period is most likely to occur (onat ha'veset), a woman must determine both:

1. The day of the month, and
2. Whether it will begin during the daytime period (sunrise to sunset) or the nighttime period (from sunset to sunrise)

 
Regular and Irregular
Every woman needs to be able to anticipate her next period, whether she is a) regular or b) irregular. “Regular” is determined by any pattern to one's menstrual cycle that occurs three times in a row.
Note It is very uncommon for a woman to maintain her regular period for a long time.
 
Anticipating a Regular Period
Here are the five most classic regular patterns:

1. Veset HaChodesh (Monthly Cycle)

   

2. Veset Haflaga (Intervals Cycle)

 

3. Veset HaGuf (Body Symptoms Cycle)

 

4. Veset HaMurkav (Combination Cycle)

    A woman with an irregular period may have to abstain from relations and affectionate intimate contact (negiya shel chibuk v'nishuk) during these three onot/time periods:

1. Yom HaChodesh

 

2. Haflaga

 

3. Ona Beinonit