If you love to make homemade cream soups and sauces, you’ve probably found yourself needing to puree them while they’re hot. Many recipes, including our own, instruct you to exercise caution, and with good reason: blending hot liquids can present a safety hazard in the kitchen. In this article, we’ll cover some essential tips and best practices for blending hot liquids safely and effectively, so you can confidently tackle any recipe that calls for this technique.
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Why can blending hot liquids present a safety hazard?
You might have heard stories or seen pictures and videos of blender eruptions from hot liquids, where the lid pops off and the contents of the blender jar end up strewn across the kitchen. (Hopefully, you haven’t experienced this yourself!)
The reasoning behind this reaction comes down to science. Hot liquids behave differently than room temperature or cold liquids when blended.
First, as liquids heat up, they expand. When you blend, the action introduces air into the liquid, causing further expansion. The outcome? Potential overflows, which could mean a kitchen mess and, more crucially, a risk for serious burns.
Secondly, hot liquids give off steam. In a sealed blender, this can create a dangerous pressure build-up. Too much pressure can push the blender lid off (quite forcefully in some cases), letting hot contents erupt from the jar.
Looking for blended soup recipes? Try our reader-favorite Homemade Cream of Mushroom Soup or Creamy Roasted Tomato Soup.
Using a Countertop Blender
Whether you’re using a traditional countertop blender or a high-speed blender, here are some tips and best practices to keep safety in mind when working with hot liquids.
- Cool First, Then Blend. Before transferring hot liquids to the blender, let them cool down a bit. This reduces steam production and potential pressure build-up inside the blender. We never blend boiling (or near-boiling) liquids. Your blender manual will often tell you the maximum temperature the model can safely handle.
- Do Not Overfill. Never fill a blender container more than halfway with hot or warm liquids to allow room for expansion. Even if the lid stays on, overfilling the container can lead to splatters escaping from the top or sides.
- Vent the Blender. Most, if not all, blender lids have a removable cap or plug in the center, covering a filler hole. On some models, like our Vitamix, this plug is vented to allow steam to escape from the jar. (Check your product manual–it will likely tell you if the plug is vented and can remain in place when working with hot liquids.) If your plug is not vented, remove it from the lid before blending hot liquids and hold a folded kitchen towel over the filler hole while blending. This will allow the steam to release and keep the liquid from spilling out and causing burns.
- Hold the Lid. Using one hand, firmly hold the blender lid down while blending. (Make sure the lid is securely seated on the blender jar!) In conjunction with Tip #3, drape a folded dishtowel over the top to add a layer of protection between you and the blender (especially an open fill hole). Holding the lid in place will prevent it from dislodging from the blending action or pressure build-up.
- Start Slow. Begin pureeing on the lowest setting. Once the liquid starts to blend smoothly, you can gradually increase the speed, if needed, until you achieve your desired consistency
- Monitor Consistently. Pay attention to the sound of the motor and any indications of pressure. If you’re holding the vented lid down with a towel, you might feel pressure building against your hand. If you do, turn off the blender and allow the contents to cool further before continuing.
- Turn Off and Wait. Once you’re finished blending successfully, turn off the blender and wait a moment for the liquid to settle before carefully removing the lid.
- Pour Carefully. When pouring the blended liquid, use oven mitts or a towel to hold the blender jar, as it may be hot. Pour slowly to prevent splashes.
- Blend in Batches. For larger quantities of soups and sauces, blend in batches. Not only is this important for safety, but it will help to ensure an even consistency of the liquid you’re pureeing, without overworking your blender blades and motor.
In the market for a new blender? We love our Vitamix Professional Series Blender {affilliate link}. Ours is an older model than the blender linked, but it has the same general profile. We’ve had it for 10 years and it still blends as well as when it was new.
Using an Immersion (Stick) Blender
The immersion blender, often called a “stick blender,” is a great kitchen tool. Its compact design and direct blending capability make it easy to blend soups and sauces right in the cooking pot.
When used correctly, stick blenders can create a fairly smooth consistency without transferring liquids between pots and blenders. Although we find that our high-speed countertop blender makes the best velvety purees, we do like using our immersion blender too.
Here are some tips for using stick blenders with hot liquids:
- Secure the Attachments. Before using your immersion blender, double-check that attachments, such as the blending arm, are securely and properly affixed.
- Depth Matters. Ensure the pot or container you’re working in is deep enough and contains enough liquid to keep the head of the stick blender submerged. This prevents the blades from splashing hot liquid outside of the pot.
- Maximum Fullness. Don’t use an immersion blender in a pot filled to the brim. It’s a good rule of thumb to keep the liquid no higher than 2/3 of the pot’s capacity to allow for expansion.
- Tilt for Efficiency. If you’re using a wider pot, slightly tilting it can help you pool the liquid to one side for better blending. (Only tilt the pot when it’s cool enough to safely do so.) Moving the immersion blender at an angle can also create a smoother flow for the liquid and a more even blend.
- Begin with Pulses. Before you move to a continuous speed with an immersion blender, start by pulsing a few times. This helps to break down larger chunks, reducing the chances of splatter. Just as with a countertop blender, we like to start on a low speed, increasing as needed.
- Sweep Through. Instead of keeping the blender static, move it around the pot in a slow, sweeping motion. Don’t lift the head above the top of the liquid while it’s turned on to avoid splatters.
- Avoid the Bottom. While it might be tempting to push the blender to the very bottom of the pot for thorough blending, you might scratch the surface if the blade doesn’t have guards. Pressing down too hard can also push hot liquid outwards, leading to potential splatters.
- Cool Slightly Before Blending. While immersion blenders can handle hot liquids, it’s still a good idea to cool things down before blending to reduce the steam and potential for hot splashes. As with a countertop blender, we don’t use stick blenders on boiling or near-boiling liquids. We usually wait 10-20 minutes, depending on the recipe and how hot the liquid was to start.
Buying a Stick Blender? Our current favorite is the Braun Multiquick 5 Immersion Hand Blender {affiliate link}.
General Safety Tips for Blending Hot Liquids
- Wear Protective Gear. Consider wearing an apron and oven mitts to protect yourself from potential splashes.
- Stay Clear. Keep your face and bare skin away from the top of the blender or pot to avoid hot splashes and steam. Be especially mindful when removing the lid after blending, which can release a puff of steam.
- Stable Ground. Place your blender or pot on a flat, stable surface. If your countertop is wet, wipe it dry to avoid any slips or movement. When using our immersion blender, we usually place the pot on a silicone trivet {affilliate link} to keep it secure and protect the countertop.
Disclaimer: The tips shared in this article are general best practices for blending hot liquids and are not exhaustive. Always use your best judgment and be familiar with your particular blender’s safety guidelines and instructions. Some models may have specific steps or features to handle steam and pressure.
