Kviat Seudah

There are two types of Mezonot foods

1. A cooked food – this is not considered bread-like and will always be mezonot.
1. Examples - porridge, oatmeal, noodles, soup nuts (deep fried) couscous, kugals, blintzes, egg rolls, donuts,
2. A baked food – similar to bread (like pat habah bekissinin), and it is only mezonot when eaten as a snack, however if eaten in a “Kviat Sudah” manner then hamotzei. (We will define this term below)
1. Examples - borekas, hotdogs in dough shell, mezonot rolls, pizza made from fruit juice, bagel chips, pretzels, crackers, biscuits, (matzah for Sephardim), and cake.

(Pancakes – Since Pancakes are cooked with very little oil, some poskim say it would be in the “baked food” category and would receive a hamotzei if you ate enough. Others argue and say it doesn’t have bread appearance and therefore wouldn’t be hamotzei no matter how much you eat. Rav Bodner poskins that when pancakes are made with very little oil, it is considered part of baked food category and would require hamotzei if one ate enough.)

Shiur of Kviat Seudah For Ashkenazim

There is a lengthy discussion about this topic and if you are interested I encourage you to read it. However, the bottom line Practical Halacha is you make a hamotzei and Birkat HaMazon whenever you eat Pas Haba Bikisnin as a meal or the amount of a meal.

As a Meal

That means, if you personally would normally eat 10 Kazayit of food for a typical meal, and one day you decided to just eat a lot of pretzels instead of your normal lunch.  If you ate 10 Kazayit of pretzels you would need to bentch, and had you known in advance you should also have washed and said hamotzei. (In practice, you don’t have to count the Kazayitim – if you eat until your feel the normal level of fullness that you feel after any meal, you know you ate the correct amount.)
Additionally, other food can combine with the Pas Haba Bikisnin to your total amount. However, there is one restriction on the foods that combine – if you would make a beracha on them during a bread meal, then they wouldn’t combine. (We discuss this…but the idea in short is that there are certain foods which aren’t connected to the meal but rather function as a desert / clean teeth. For a simple example, take fruit, most times one would need to make a new beracha on fruit even if eaten during a bread meal. Therefore the volume of the fruit would not contribute to your total volume in creating kviat seudah.)
Therefore as long as you eat 1 KaZayit of Pas Haba Bikisnin, and then you fill yourself like you would normally during a meal with soups, salads, meats, vegetables, (almost) anything – then you should bentch. 
It is important to note that while you can eat these foods for hours and have them add up – at least one KaZayit of Pas Haba bikisnin must be eaten in a 4 minute time period. (see discussion on C’dei Achilat Pras)

The Amount of a Meal

Say you don’t eat it as a meal, but rather at 3pm you are hungry for a snack. If you would eat the amount of food that you normally eat for a meal right then and there – you would need to bentch. For example, if you eat 10 Kazayit of pretzels at 3pm – you must bentch. Even if you call it a “really big snack” – it is halachically a meal.

What about the 3 or 4 Egg Standard

The Mishna Berura and many poskim advise that one should take the chumrah of watching for this opinion as well. Therefore even if one’s personal amount is 15 Kazayit – if he would eat only 8 Kazayit there would be a safek if he should bentch. The poskim advise that if one feels full from just those 8 he should bentch and if not he should say Al Hamichya.
However we wouldn’t combine other foods when going for this smaller shiur. So those 8 Kazayit must be from Pas Haba Bikisnin alone.

Size of a Kazayit

Keep in mind that a Kazayit really isn’t that big. 1 Kazayit is equal to the volume of 1 fluid ounce. So picture an 8 ounce plastic cup and that is the shiur kviat seuda according to the smallest opinion. That means if you cut a generous slice of chocolate cake, it would probably be around 8 Kzayit. Imagine stuffing the cake into our cup – would the cake fill up the entire cup? If so, then you have already eaten enough for this opinion and you would not need to ask yourself if you are just as full now as after a normal meal. People eat around 20 ounces at a meal, so most likely you’re probably not full yet, and you should only say Al Hamichya. However, if you eat other foods, and so much of them that you have now eaten what your normal is – then you would bentch.
Keep in mind, Kazayit are measured in volume and not in weight. So if the slice was in brownies instead of cake, you would probably get much more full from less Kazayitim since they are so dense. Meaning, a normal guy could probably eat 8 Kazayit of chocolate cake no problem, but only 4 Kazayit of brownies.

Shiur for Sephardim

1) Many Sephardim go by weight, while others go by Volume and both are acceptable and each should keep their own minhag.
If you are going by weight, each Kazayit weights 28 grams and a shiur seudah would be around 230 grams.
If you are going by volume, each Kazayit is one fliud once and the shiur seudah is 8 ounces.
Most of the time the two methods should be very close together, however there are some foods which are at the extremes of either really dense or really light that make differences.

2) Regardless of your method, Sephardim in general agree that one doesn’t include other foods. The shiur is determined using pure Pat Habah BiKisonin.

3) Four beitzah, or 8 Kazayit creates a definite obligation to bentch. However, according to the Rambam, one only needs to eat 3 Beitzah or 6 Kazayit to bentch. Therefore, we poskin that out of uncertainty, one should avoid eating between 6 and 8 Kazayit. Either eat less than 6 and say Al Hamichya. Or eat more than 8 and bentch.

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