Pictures: Large industrial stove, oven, fryer, elegantly set ballroom with tables

Mendy enjoyed his job at Elegant Touch Catering (ETC). His primary responsibilities were in the office, but his sharp eye was noticed by Rabbi Ephraim Rubin, the caterer’s veteran mashgiach, who needed extra help with vegetable checking. Finding people with the skill and acumen to determine acceptability of leafy greens, especially in the pressurized environment of a commercial kitchen, was a challenge for Rabbi Rubin and he was eager to recruit Mendy as an assistant.

After two months of training, and hours squinting in the harsh glow of a light box covered by microfiber mesh cloth, Mendy became adept at detecting tiny translucent thrips and aphids hiding in the folds and crevices of romaine, kale, broccoli, dill, and parsley. Finally, the STAR-K  Kashrus Administrator overseeing foodservice establishments approved him as a vegetable checker. Eventually, Mendy finely honed his skills to the point of finding insects in vegetables that were previously checked by fellow workers. This forced everyone in the kitchen to upgrade their vigilance.

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Mendy decided to expand his kosher credentials, and began accompanying Rabbi Rubin to off-site venues where the non-kosher kitchen was  kashered² before an event. For weddings,  bar mitzvahs, and other standard occasions, all the food was prepared in the commissary and only required re-heating. Consequently, it was sufficient for the kashering team to arrive just a few hours in advance. Mendy quickly picked up the routine, and he found it useful to draft a checklist of general tasks.[See Sidebar]
Mendy learned that  kashering was much easier than he previously assumed. The difficult part is the preparatory work, making sure everything is completely clean.  Kashering  is ineffective when bits of grime, grease or rust remain on a utensil. Although hotel managers are reminded to thoroughly clean the kitchen, Mendy frequently observed how Rabbi Rubin would gently explain to kitchen staff that the job was not yet complete. Our kosher standards of cleanliness exceed what is normally acceptable by their standards. When preparing to  kasher, the proper instruction is to clean the equipment until it looks like new!

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Once, while setting up a kitchen at a country club for a wedding, Mendy noticed that some of the soup servers coming off the caterer’s truck were marked in blue paint with the letter “D”, denoting ‘Dairy’. Since it would take two hours for  fleishig (meat) pots to be delivered from the commissary, Mendy thought valuable time could be saved by merely  kashering  the  milchig (dairy) pots. He verified that they weren’t used during the previous 24 hours, and carefully checked for cleanliness, especially the area around the rim where food particles can get stuck. Mendy was familiar with the custom not to  kasherback and forth from dairy to meat and vice-versa;³ he also knew the work-around.  Pots could be rendered non-kosher, and when subsequently  kashered they could be designated with any status (meat, dairy,  pareve).⁴ He asked the head waiter for a bottle of non-kosher wine and an empty #10 ketchup can in which to heat the wine. Pouring hot wine into the dairy pots would render them non-kosher.

Proud of his quick thinking, Mendy went to Rabbi Rubin for approval before proceeding. His satisfaction quickly faded when the rabbi reminded him that the pots were un- kasherable because of the paint markings.  Chazal never discussed a method to  kasherpaint and, therefore, we must assume that any non-kosher (or dairy or meat) absorptions cannot be extracted from the paint layer.⁵ In addition, as a matter of policy to prevent mistakes, pots are generally not  kashered  on the day of an event. Mendy humbly acknowledged that he still had more to learn.

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One year after adopting his new role, Mendy received a call from the president of  B’nei Israel Congregation. He wanted ETC to cater their upcoming weekend retreat at a resort in the mountains of Western Maryland. Mendy’s first question was whether or not the facilities were  Shabbos compliant, and specifically, whether the electronic door locks could be bypassed. Due to the large group in attendance, STAR-K required that three mashgichim be present throughout the event. Allowing ample time for any unexpected surprises, Rabbi Rubin and Mendy planned to  kasher the kitchen early, on the previous Wednesday.

Standard procedure is to  kasher only devices used for re-heating food, or for cold food preparation. ETC submitted a request to their STAR-K administrator to permit  kashering the resort’s deep fryer so that fried chicken and potatoes could be prepared fresh for Sunday dinner. The request was granted as the  kashering  process would begin three days prior to the event. Consideration was also given to the knowledge and expertise of ETC’s mashgichim. This decision was contingent upon the cleanliness of the fryer.

Late Tuesday night, Mendy received a telephone call from Rabbi Rubin. His son just became a  chosson! The rabbi informed Mendy that in the morning, he would be travelling to New York for the  l’chaim. He added, “I already called the  Rav HaMachshir and he gave his approval for you to handle the  kashering. I’m really sorry about this, but I know that you’ll be fine without me. ”

“But,” protested Mendy, “I’ve never  kashered a fryer by myself!”

Rabbi Rubin had full confidence in his protégé, knowing that Mendy was studying the halachos of  kashering  in the evenings after work. “Call me from the resort and we’ll work it out together.” The next morning, Mendy  davened  Shacharis with intense  kavanah that everything should go smoothly.

It was hard to find another available  mashgiach on such short notice. In the end, Mendy found his neighbor Yossi, who was home from  yeshiva and had some catering experience working during  bein  haz’manim. Arriving at noon, they stopped at the office and went straight to the kitchen. From the first moment, Mendy knew things were not going to go smoothly. He waited patiently as the kitchen manager showed them around, boasting about the cleanliness. Then, pointing to some otherwise innocuous looking streaks and rust spots,⁶ Mendy explained in the most delicate terms that although by industry standards it was a clean kitchen, by kosher standards there was still work left to be done. “We need everything to be clean and looking like new!”

The cleaning team was brought in and got down to work. Mendy and Yossi filled two large 100 quart pots from the commissary with water and turned on the fire. Mendy told Yossi, “It will take a while for these pots to boil, so let’s get started on something else.”

Let’s add salt to the water to help speed up the boiling,” suggested Yossi. “That’s what my mother does at home.”

“No,” answered Mendy. “Rabbi Rubin always says the  kashering water must be pure.”

Just then, Rabbi Rubin called. “How is everything going?” Mendy reported on the current state of affairs and what had been accomplished up until then. He then mentioned Yossi’s suggestion about the salt. Rabbi Rubin explained that since there is a disagreement in the Poskim about whether  kashering is effective with liquids other than water, we are careful to  kasher with plain water only.⁷ “However,” added Rabbi Rubin, “there are other ways to speed up the water boiling, such as covering the pots.”⁸

Rabbi Rubin continued, “Assuming that you are using a standard commercial gas stove with 30 thousand BTU per burner, and each pot was filled with 24 gallons of water, you easily have more than an hour until they boil.” Rabbi Rubin was fond of displaying his technical knowledge. “Perhaps now is a good time to look at the deep fryer. Please keep me posted.”

Mendy and Yossi moved away from the hot and humid area around the stove, past the busy workers who were scrubbing and scraping, and went to inspect the fryer. “I hope you fellows won’t be poking around there with a blow torch, like I saw a rabbi do one time,” remarked a nearby resort maintenance worker. “That Frialator cost $2500 plus installation, and we take mighty good care of it.”

Essentially, the fryer is a big pot filled with oil that has baskets inserted inside to hold the food. In this older model, fire shoots through two gas-powered heating tubes sitting near the bottom which quickly heat oil to a high temperature. Mendy was grateful that the fryer was in excellent condition, and was as clean as one could expect for a machine that could hold 90 pounds of sizzling oil. Judging from the recipe card for fried shrimp hanging on the wall, this piece of equipment was bona fide not kosher. Mendy ran his finger around the walls and the bottom of the fryer and, to his surprise, it was free of grease. He surmised that they must use a powerful de-greaser to clean it. Therefore, it could be kashered  by simply filling it with water and turning on the heat.

Revisiting the pots on the stove, Mendy lifted the lid and peered in to see how far it had progressed towards boiling. He saw bubbles forming, and estimated that it was almost ready. Meanwhile, Yossi had returned to the office to retrieve his knapsack and took out an infrared heat gun that he purchased for his last  hashgacha job. After adjusting the setting for stainless steel pots, he pointed the beam inside the water. “Only 205°F,” he shouted over the kitchen noise. “I think it still needs a while yet to go.”

“Temperature doesn’t matter,” Mendy responded. “Look at the bubbles.”

“What do you mean?” Yossi said hotly. “The  Rav HaMachshir for whom I usually work insists that  kashering water must be 212°F. Feel free to use a lower standard, but don’t involve me!”

“My dear Yossi,” replied Mendy. “If you want to wait until this pot reaches 212°F, Moshiach will arrive and you’ll still be waiting! 212°F is the temperature of boiling water at sea level. But we’re in the mountains, where the atmospheric pressure is lower. At our elevation of 2700 feet, water boils at just 207°F.”

Mendy continued his point. “The  halacha is clear that  hagolah (purging with hot water) removes  beliyos, absorbed tastes, through the bubbling action.⁹ The  type of heat source is significant, but not the  temperature. That’s why boiling water can  kasher  items that usually operate at much higher temperatures.¹⁰ For instance, oil in a deep fryer reaches 400°F, and liquid in a pressure cooker reaches 600°F. Both items are  kashered  through boiling water, because the  risicha, bubbling, is what works.¹¹ The opposite also holds true,” explained Mendy. “If you were  kashering  at a hotel near the Dead Sea, which is almost 1400 feet below sea level, you would need to wait until the water boils at 214°F.”

As Yossi nodded his head to indicate his understanding, Mendy’s phone rang. It was Rabbi Rubin. Over the music and singing in the background, the rabbi asked about the state of the deep fryer. He was relieved to hear how clean it was. “Excellent,” remarked Rabbi Rubin. “By the way, did you check the heating tubes?”

“No,” answered Mendy. “I carefully examined the cooking chamber, but I didn’t think to check those tubes. I’ll go take a look right now.” Phone to his ear, Mendy looked in and noticed some black specks on the heating tubes, which felt slightly raised when he rubbed his hand over them. “Are they a problem?” he asked.

“Yes,” said Rabbi Rubin. “Frying generates an intense heat, which produces carbon that can become embedded on the tubes. Degreasers don’t remove them, and we can’t  kasher with  hagolah  as long as they remain. The only effective method that I know of is to boil pure ammonia in the fryer for 20 minutes.¹² No need to fill it all the way, just above the level of the tubes is good enough. If this works, you can then  kasher  using plain boiling water afterwards. Remember that you must also  kasher  the outside of the fryer, by letting the boiling water cascade over the sides.  Hatzlacha, I wish you success!”

By now, it was already evening and Mendy and Yossi took a break to  daven  mincha. When they returned, the cleaning team was putting away their supplies and preparing to leave. Mendy felt bad asking them to stay to take care of yet another task, but he had no other option. The maintenance technician was relieved that no blow torches were being used, but wasn’t quite sure what to make of the ammonia plan. As they were bringing ammonia from the secure chemical room, Mendy’s phone rang. It was Rabbi Rubin again. What could he want?

With urgency in his voice, Rabbi Rubin said, “And make sure to open all the windows and turn on the exhaust fan. The last time we boiled ammonia, one of the workers passed out on the floor from the fumes! We carried him out to fresh air and he was okay, but don’t take any chances. Also, it’s important that the drain, hoses and gaskets on the bottom of the fryer be thoroughly cleaned. They’re probably full of non-kosher grease and will affect the kosher status of whatever is fried inside.” Mendy heard someone shout, “ L’chaim !” and the phone connection was broken.

It was already very late by the time the kitchen was satisfactorily  kashered. The doors were sealed with tamper-proof tape to ensure that the kosher status remained intact until Friday. On Friday afternoon, Mendy was walking outside near the resort lobby as cars pulled up. He spotted Rabbi Rubin’s car and ran over shouting “ Mazel Tov!” as he gave the rabbi a hug.

“Congratulations to you!” exclaimed Rabbi Rubin. “For the fabulous job you did  kashering the kitchen!”

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1. Adapted from a  shiur delivered by Rabbi Shmuel Heinemann at the STAR-K FOODSERVICE MASHGIACH TRAINING SEMINAR, July 2013. Rabbi Mayer Kurcfeld, an invaluable resource in the area of foodservice  hashgacha  with a wealth of practical knowledge, also contributed to this article.

2. This is the Yiddish term for making equipment and utensils fit for kosher use. The procedure employed depends on how the utensil was used.  Hagolah , libun chamur and libun kal, or  iruy are various methods  of  kashering.

3.  Mishna  Berurah, 451:19, quoting  Magen  Avraham 509:11.   He cites the  Chasam  Sofer ( Shu”t  Y.D.110) who says that when  kashering  for  Pesach one may also switch the dairy/meat designation. Common practice dictates that this  minhag  applies only when  kashering  with  hagolah, but not libun. (See  She’arim  Mitzyunim B’Halacha 46:15 and  Chelkas  Binyamin 121:33.)

4.  Mishnah Berurah, 509:25, from  Pri  Megadim, Eishel Avraham, 509:30.

5. This is a concern when  kashering  with  hagolah, which works by drawing out the tastes absorbed in the walls of the utensil. In contrast,  libun  gamur  burns absorptions in their place and works in almost all circumstances.

6. Discolorations and stains don’t affect  kashering ( Mishna  Berurah 521:22), only actual residue or rust, even a minimal amount.

7.  Rema , Orach Chaim, 552:5.  This policy is most relevant when producing  pareve chocolate on equipment previously used for dairy, since chocolate producers avoid introducing water into their equipment. Therefore, STAR-K certifies chocolate as  pareve only when produced on a dedicated line.

8. Applying heat on the sides of the pot with a propane torch can also help speed things along.

9. See  Shulchan  Aruch, Orach Chaim, 252:1,  Shulchan  Aruch HoRav 252:3.

10. See  Kitzur  Shulchan Aruch ( Rav Aharon Pfeifer)  Basar  B’chalav II, Appendix 1, in the name of Rav Shlomo Zalman Auerbach.

11. In some specialized equipment, such as reactors found in flavor companies which operate in a near vacuum, water will bubble furiously at a mere 60°F, cool to the touch. In this situation, we require at least a temperature of  yad  soledes bo, which here can be assumed to be 120°F.

12. The non-sudsing type should be used. Otherwise, it will bubble over and all of the ammonia will boil out. Without liquid inside, the fryer will be ruined.