How to Pasteurize Raw Milk at Home: 3 Safe Methods (Stove, Pasteurizer, Instant Pot)

What Pasteurization Actually Does

Pasteurization heats milk to a specific temperature for a specific amount of time to kill pathogenic bacteria including Listeria, Salmonella, E. coli O157:H7, and Campylobacter. It does not sterilize milk, meaning some non-pathogenic bacteria survive and the milk will eventually spoil. What it does is reduce pathogen load to a level that is safe for drinking and cooking.

The two protocols recognized by the FDA for home and small-scale pasteurization are:

• LTLT (Low Temperature Long Time): 145°F (63°C) held continuously for 30 minutes. Also called vat pasteurization. The preferred method for home dairy because it is gentler on flavor, easier to hold accurately without commercial equipment, and better for milk you intend to culture.
• HTST (High Temperature Short Time): 161°F (72°C) held for 15 seconds. Standard for commercial dairies and faster, but the 15-second window is difficult to hit precisely without automated flow-through equipment. At home, this method is better approximated by heating to 161°F, holding briefly, then cooling immediately.

A third temperature you will see is 180°F or higher, sometimes called flash pasteurization or ultrapasteurization. Heating to this range does pasteurize milk, but it also damages whey proteins and produces a faintly cooked taste. It is not recommended for milk you plan to use for cheese or yogurt, and it is not necessary for food safety purposes when either LTLT or HTST will do the job.

What You Need Before You Start (All Methods)

• A reliable dairy or instant-read thermometer: Temperature accuracy is the entire job here. A thermometer that reads 3 to 5 degrees off means you are either under-pasteurizing or over-heating. Calibrate yours in boiling water (212°F at sea level) before relying on it.
• Clean, food-grade containers: Sanitize all jars, lids, and pitchers before filling with pasteurized milk. Pasteurized milk put into a container carrying residual bacteria from the previous batch will spoil just as fast as raw milk.
• An ice bath: After pasteurizing, you want to cool milk from 145°F down to 40°F as quickly as possible. Fill a large bowl or clean sink with ice water before you start. The faster the cool-down, the longer the milk keeps and the better the flavor.
• Fresh raw milk: Pasteurization does not improve poor-quality milk; it reduces pathogen risk in quality milk. Start with clean milk from healthy animals, handled hygienically from the moment of milking.

Method 1: Stovetop Double Boiler (LTLT)

The stovetop method is accessible for anyone, requires no special equipment beyond a thermometer, and works for occasional small batches. Its limitation is that it requires your full attention for 30 continuous minutes to maintain the hold temperature.

What You Need

• A large pot for the water bath (outer)
• A smaller stainless steel pot or bowl for the milk (inner)
• A dairy or instant-read thermometer
• A stirring spoon
• A timer

Steps

1. Fill the outer pot with water and set it on the stove over medium heat.
2. Pour your raw milk into the inner pot and nest it in the water bath. The water should come up at least halfway on the sides of the inner pot.
3. Heat, stirring occasionally, until the milk reaches 145°F. This typically takes 15 to 25 minutes depending on milk volume and stove output.
4. Start a 30-minute timer the moment the milk hits 145°F. Stir every 2 to 3 minutes throughout the hold period. Adjust burner heat to maintain 145°F to 150°F. If temperature drops below 145°F, the 30-minute hold starts over from zero.
5. After 30 minutes of continuous hold at 145°F or above, remove the inner pot and transfer it immediately to your ice bath.
6. Stir the milk in the ice bath to accelerate cooling. Target 40°F within 30 to 60 minutes. The faster it cools, the longer it keeps and the fresher it tastes.
7. Pour into sanitized containers and refrigerate immediately.

The honest downside: Thirty minutes of active monitoring is a real time commitment every session. If you are pasteurizing 1 to 2 gallons twice a week, that is two hours of kitchen attention per week, year-round. For occasional batches it is fine. For regular family dairy production, the next two methods solve this problem.

Method 2: Dedicated Milk Pasteurizer (LTLT, Hands-Free)

A dedicated pasteurizer is a double-walled stainless steel vessel with a water jacket and a built-in thermostat. You fill it, set the temperature, and walk away. It holds 145°F automatically for the entire 30-minute hold period and alerts you when the cycle is complete. No stirring, no watching, no timer on your phone.

The Milky Day FJ pasteurizer line is designed around exactly this workflow. The double-wall construction heats milk evenly from all sides through the water jacket, which eliminates the hot spots that cause scalding in direct-heat vessels. The built-in thermometer and thermostat hold the target temperature within a narrow band throughout the cycle.

The additional advantage that most buyers do not realize until after purchase: the FJ pasteurizer is also a cheese kettle and a yogurt incubator. The same unit that pasteurizes milk on Monday can hold it at 90°F for mozzarella curd on Tuesday and maintain 110°F for a yogurt culture on Wednesday. One piece of equipment covers three major dairy processes. For a full breakdown of which FJ model fits your milk volume, read our guide to milk pasteurizers.

How to Pasteurize with a Milky Day FJ Pasteurizer

1. Fill the water jacket of the FJ unit to the fill line with clean water.
2. Pour raw milk into the inner stainless vessel up to the maximum fill line for your model.
3. Set the thermostat to 145°F. The unit will heat the water jacket, which heats the milk evenly and without direct contact between the heating element and the milk.
4. The built-in stirring arm keeps milk moving throughout the heat cycle, which prevents surface skin formation and ensures uniform temperature throughout the batch.
5. When the milk reaches 145°F, the unit holds it there automatically. Set a 30-minute timer if your model does not have an automatic hold-and-alert cycle.
6. After 30 minutes, move the inner vessel to an ice bath or switch the FJ unit to cooling mode if your model supports it. Cool to 40°F as quickly as possible.
7. Transfer to sanitized containers and refrigerate.

Browse the Milky Day pasteurizer collection to compare FJ models by capacity.

Method 3: Instant Pot Sous Vide Function (LTLT)

The Instant Pot is not a dairy pasteurizer, but on models with a sous vide or precise temperature-hold function, it can perform LTLT pasteurization accurately enough for small batches. This method works specifically for the Duo Evo Plus, Ultra, and Precision Cooker models that hold temperatures within 1 to 2 degrees Fahrenheit. It does not work reliably with the standard yogurt "boil" cycle, which overshoots to approximately 180°F rather than holding at 145°F.

Using the Sous Vide Function

1. Pour raw milk into a quart-size mason jar or sealed food-safe bag.
2. Fill the Instant Pot inner pot with water to just below the jar lid or bag seal.
3. Set the sous vide function to 145°F for 35 minutes (the extra 5 minutes accounts for time-to-temperature).
4. Once complete, move the jar or bag immediately to an ice bath and cool to 40°F.
5. Transfer to a clean container and refrigerate.

Honest limitations: The Instant Pot sous vide function handles 1 to 2 quarts practically. For a family dairy processing 3 or more gallons at a time, you would need to run 4 to 6 consecutive cycles, which defeats the time advantage. The Instant Pot method is best for households that milk occasionally, process small volumes, or are evaluating whether regular pasteurization is worth building a dedicated setup around.

It is also worth noting that not all Instant Pot models hold temperature precisely. Check your model's specs before relying on this method. If your thermometer shows the milk temperature wandering more than 3 to 4 degrees from 145°F during the hold, the stovetop double boiler method with careful attention gives you more control.

Method Comparison at a Glance

Pasteurizing Milk for Cheese or Yogurt: What Changes

If you are pasteurizing milk with the intention of culturing it into cheese or yogurt, the method and temperature choice matter beyond just food safety.

Use LTLT at 145°F for 30 minutes. The higher heat of HTST at 161°F and certainly any temperature above 170°F begins to alter whey proteins in a way that affects how cultures behave. Milk pasteurized at 145°F cultures faster and more consistently, produces cleaner curd set in cheesemaking, and yields thicker yogurt with better texture than milk heated to 161°F or above.

Do not use ultra-high-temperature milk (UHT, the shelf-stable kind in cartons) for cheesemaking even if you warm it to curd temperatures. The proteins in UHT milk are damaged to the point where they will not set curd reliably regardless of what culture or rennet you add.

After pasteurizing milk intended for culturing, cool it to the target inoculation temperature as specified in your recipe rather than all the way to 40°F. For mozzarella, that is around 88 to 92°F. For yogurt, it is 108 to 112°F. Add your culture directly as the milk hits that range while it is still in the pasteurizer vessel, then let the FJ unit hold that temperature for the incubation period. One vessel, one heat cycle, one cleanup.

For the full cheesemaking workflow using a Milky Day FJ pasteurizer as a cheese kettle, read our guide on how to make cheese at home with a milk pasteurizer. For yogurt specifically, see our raw milk yogurt guide using the pasteurizer method.

Cooling and Storage After Pasteurizing

How quickly you cool pasteurized milk after the heat cycle directly affects how long it keeps. The goal is to drop temperature from 145°F to 40°F in under 60 minutes. The faster, the better.

The most effective method at home is an ice bath: fill a large bowl or your kitchen sink with ice water, place the milk vessel in it, and stir the milk every few minutes. A 1-gallon pot cools in 20 to 30 minutes in a properly iced bath. A 4-gallon FJ pasteurizer vessel takes 40 to 60 minutes with regular stirring and ice replenishment.

Once cooled to 40°F or below, transfer to sanitized glass or food-grade plastic containers, seal tightly, and refrigerate. Home-pasteurized milk keeps 7 to 14 days at 40°F. Keep it at the back of the refrigerator where temperature is most stable, not in the door where it fluctuates with each opening.

Frequently Asked Questions

What temperature do you pasteurize raw milk at home?

The two FDA-recognized temperatures for home pasteurization are 145°F (63°C) held for 30 minutes (LTLT method) or 161°F (72°C) held for 15 seconds (HTST method). For home dairy, LTLT at 145°F for 30 minutes is the standard recommendation because the longer hold time is far easier to achieve accurately without automated equipment. The 15-second HTST window requires precise temperature control that is difficult to hit manually.

Can you pasteurize raw milk in the microwave?

No. Microwave heating is uneven and creates temperature hotspots that may reach 180°F in one part of the milk while other areas remain below 145°F. Pasteurization requires uniform temperature throughout the entire batch for the full hold period. A microwave cannot deliver this. Use a stovetop double boiler, a dedicated pasteurizer, or the Instant Pot sous vide function on compatible models.

Does pasteurizing raw milk destroy the nutrients?

LTLT pasteurization at 145°F causes modest nutrient reduction compared to raw milk. Vitamin C loss is approximately 10 to 25%, though raw milk is not a meaningful source of vitamin C to begin with. Some heat-sensitive enzymes including alkaline phosphatase and lactoperoxidase are denatured. The protein, calcium, fat, and most vitamin content of the milk is essentially unchanged at LTLT temperatures. HTST at 161°F and especially UHT processing at 280°F+ causes progressively more damage to whey proteins. This is why home LTLT pasteurization is often described as gentler than the ultra-pasteurization used in commercial shelf-stable dairy.

How long does home-pasteurized milk last?

Home-pasteurized milk kept at 40°F or below lasts 7 to 14 days. Raw milk lasts 5 to 10 days under the same conditions. The variation depends on how quickly the milk was cooled after pasteurization, how clean the containers are, and how consistently the refrigerator holds 40°F. For complete shelf life data on raw milk, pasteurized milk, cream, butter, and aged cheese, see our guide on how long pasteurized milk lasts.

Do I need to pasteurize milk before making cheese?

It depends on the cheese and your jurisdiction. In the United States, cheese made from raw milk must be aged a minimum of 60 days before sale under federal law. Under-60-day soft cheeses sold commercially must be made from pasteurized milk. For home use and personal consumption, raw milk cheese is legal in most states. Pasteurizing milk before cheesemaking reduces pathogen risk, especially for soft fresh cheeses like ricotta, chevre, and mozzarella that are consumed within days. Aged hard cheeses carry lower risk even from raw milk because the aging process (acidity, salt, moisture reduction) is itself hostile to most pathogens.

Conclusion

Pasteurizing raw milk at home is straightforward when you know the temperature and time targets. For occasional batches, the stovetop double boiler does the job with equipment you already own. For a family processing several gallons multiple times per week, a dedicated FJ pasteurizer replaces 30 minutes of active monitoring with 5 minutes of setup and a walk-away cycle that also handles your cheesemaking and yogurt incubation.

If you are building or upgrading a home dairy, the pasteurizer is the piece of equipment that does the most work per dollar. Browse the Milky Day pasteurizer collection to find the right FJ model for your milk volume, or read our pasteurizer buying guide for a full comparison of models and sizes.