Shulchan Aruch Chapter 611:
Yom Kippur at night has the same laws as during the day (2 Paragraphs)
Note: The REMA is in brackets 
1. The night/eve of Yom Kippur is identical to the day in all aspects. What things are forbidden to do on Yom Kippur? Work, eating and drinking, washing, anointing, wearing leather shoes and relations. However, you only incur the penalty of כרת (excommunication) for working, eating and drinking.
2. Any type of work that is considered violating Shabbat is considered violating Yom Kippur. Any type of work that falls under the category of “exempt but forbidden” (פטור אבל אסור) on Shabbat, also does for Yom Kippur. The only difference is that if one violates Shabbat (purposefully) he is punished with stoning, but if one violates Yom Kippur he is punished with excommunication. Anything that is forbidden from being moved on Shabbat is forbidden to move on Yom Kippur. But they permit stripping of vegetables and crushing nuts from the time of Mincha and later if Yom Kippur fell out on a weekday. However, nowadays the custom is to forbid these things. [If a fire falls out on Yom Kippur, it is permissible to save one meals worth of food since that is needed for the nighttime just like we save the afternoon meal on Shabbat. I already explained in Ch. 334 how we deal with a fire occurring on Shabbat nowadays and the same applies for Yom Kippur. The custom is for children to measure (quantities of) nuts and you should not protest even if they are doing so before Mincha. This is like the custom of crushing nuts already mentioned.]
Chapter 612: The prohibition on eating on Yom Kippur and the measurement
1. One who eats on Yom Kippur the measurement of a large date (ככותבת הגסה) is guilty; which is a little less than the size of an egg. This measurement is the same for every person, whether he is a dwarf or Og the King of Habashan.
2. All foods are combinable to this measurement; even the salt on meat and the brine on vegetables. But eating and drinking are not combinable.
3. If one ate and then returned to eat again, if one waited from the first bite until the last less than it takes to eat a piece of bread (כדי אכילת פרס) it is combinable. And if not, it is not combinable.
4. Regarding the measurement of eating a piece of bread, some say it is four eggs and some say it is three eggs.
5. This measurement is required to incur the penalty of excommunication (כרת) or to bring a sin offering (if done accidentally) but it is still forbidden to eat any amount.
6. If you eat something that is not fit for consumption or if you ate an excessively large amount like right after you ate on Erev Yom Kippur until you were disgusted with the food, you are exempt. [And if you eat spiced or seasoned foods, you do incur the penalty since usually benefit is derived from the spices. It is forbidden on Yom Kippur to taste something and then spit it out, even a branch of a spice plant. See 567:3. ]
7. If you ate עלי קנים, you are exempt. Grape twigs that sprout before Rosh Hashanah are also exempt since they are only wood. And if they sprouted (in Israel) from Rosh Hashanah until Yom Kippur, you are liable.
8. If you chewed [he means you chewed and mashed with your teeth] peppers or ginger, if they were dried out you are exempt since they are not fit to eat. But if they were moist you are liable.
9. If you drank on Yom Kippur enough for a cheek full, you are liable. The same measurement is relative to all people according to how big or how small they are. This does not mean an actual cheek full; rather it means enough to put to one side of your mouth so it looks like a cheek full. This measurement is less than a רביעות for the average person. All drinks are combinable for the measurement. [If you drink something that is not fit for drinking like brine and live vinegar you are exempt. But diluted vinegar is liable.]
10. If one drank a little bit and drank again, if the time from the first drink to the last drink was less than the time it takes to drink a רביעות, they are combinable to make the measurment. And if not, they do not join together. Some say that the measurment is less than it takes to eat a piece of bread (כדי אכילת פרס) like the measurement for eating. [It is permitted to touch food and drinks on Yom Kippur and to give them to kids and we are not afraid that you will eat or drink if you touch them.]
Translated by Jay Dinovitser www.shulchanarach.com
 M.B: One view is this means removing the leaves from the stalk in order to prepare it for after Yom Kippur. Others view this as a different act of preparing vegetables for after Yom Kippur.
 Literally “wounding nuts”. To use after Yom Kippur is over. Crushing nuts or stripping vegetables for eating on Shabbat is permitted but you should not do it on Shabbat to use when Shabbat is over.
 M.B: The reason why the custom changed is that people erred and starting doing these things before Mincha Kettana so they abolished it.
 M.B: Even though all similar transgressions of the Torah occur by the size on an OLIVE, this applies only when it mentions eating and drinking. But on Yom Kippur, the Torah did not write eating but says “the soul that did not fast...” Therefore, the measurement on Yom Kippur is a smaller quantity, the size of a large date. See the next footnote for the size of an egg.
 Each egg size is about 62 grams (R’ Moshe Fienstein but this is a topic of great debate) bringing to total weight to 186 grams or 248 grams.
 M.B: You still incur the penalty for the food you ate before you were disgusted.
 M.B: But it is permitted to smell spices on Yom Kippur.
 This is some type of leaf. I don’t know the meaning.
 M.B: Because they are soft and fit to eat.
 As explained later, this means the quantity to fill one cheek.
 The S.A. uses two words that both mean brine, so I only list one here.