Double pitching and co-pitching are two different techniques to alter the fermentation process of your beer, wine, or spirit wash. Double pitching involves adding more of the same yeast, while co-pitching is where two different yeast are mixed together to get a particular flavor, aroma, or fermentation characteristic.
Both are somewhat controversial topics in the brewing industry.. So what’s the verdict? when can you double or co-pitch?
Let’s find out.
What Is Double Pitching?
Double pitching is the process of doubling the amount of yeast a recipe calls for. It’s often used to fix a stalled fermentation and to ensure you achieve your final gravity target.
The idea of double pitching is a controversial topic amongst brewers and home distillers and brewers. Most feel it’s an excellent technique to save a stuck ferment. Others believe it’s a waste of resources because it can result in overpitching.
While we agree with both schools of thought, it’s worth noting that double pitching does have its place.
Double pitching not only fixes your stuck fermentation, but it also ensures you achieve your desired final gravity. And if you’re lucky enough, it can add flavor to your final product.
When double pitching, you often use the same strain of yeast. And yes, there are some downsides to this.
If you exceed the pitch rate, you might end up with an overpitched yeast. That’s when off-flavors derived from compounds like diacetyl and fusel oils make an appearance in your final drink.
Below’s an in-depth explanation of when you might need to double-pitch.
First, Can you pitch yeast twice?
Yes, You can pitch yeast twice.
When doing so, you need to have proper fermentation control.
That means ensuring your ferment is at optimal fermentation temperatures and your equipment is properly sanitized.
Pitching twice can lead to some nasty surprises.
Instead of speeding up fermentation, it negatively affects the flavor of your alcohol by releasing compounds like diacetyl and fusel oils into your wash.
1. Pitching again during primary fermentation
When you wind up at a low final gravity, you can pitch yeast to your primary fermentation. It helps your wash to ferment dry.
2. Pitching again during secondary fermentation
Sometimes, you might find yourself in a situation where you need to pitch again during secondary fermentation. Below’s an example of such an instance.
- When it’s time to rack your ferment and realize it hasn’t reached your desired final gravity.
- When using yeast cake, pitching again eats away at any remaining sugars for a dry ferment.
3. Pitch to fix a stalled fermentation
When you take a gravity reading and it lingers somewhere around 1060, it means you’re experiencing a stuck fermentation.
Several other factors make for stalled fermentation. These include low fermentation temperature, using a strain that doesn’t ferment longer chain sugars, and not adding enzymes.
Adding yeast, especially one that attenuates well, will boost your fermentation.
If you didn’t add enzymes, it’s best to add yeast nutrients because some would’ve been used up in the initial wash.
What Is Co-Pitching Yeast
Looking to add new aromas to your final spirit? You should try co-pitching.
Co-pitching or co-fermenting is the process of adding two different yeast strains to obtain a myriad of flavors. It’s a technique employed by commercial brewers and distillers because it allows them to create fun, fresh and unique beverages. When co-fermenting, a strain with low attenuation is typically paired with one that’s highly attenuative to help see fermentation through.
Most yeasts are suited for specific effects. That’s why you’ll find cider, whiskey, beer, and rum yeasts.
By co-pitching, you’re able to combine the flavor compounds of various strains to produce a unique final spirit. It’s a common technique amongst craft beer beers and distillers because it allows them to experiment with different yeast esters to create exciting flavors.
When co-pitching, it’s best to add a strain that’s least attenuative for the desired flavor. After a couple of days, when the yeast starts to stall, you can add a strain with faster attenuation to carry the process till you reach your final gravity goal.
If you decide to go down this route, we recommend you pitch a strain you’re familiar with. That means you know its ideal fermentation temperature, pH tolerance, and viable cell concentration.
So, what are the pros and cons of co-pitching? Let’s explore that below.
Advantages of co-pitching
- It allows you to create authentic flavor profiles.
- Ensures your wash, wort, or must ferments dry.
- By using two yeasts with different attenuation levels, you’re less likely to have a stuck fermentation.
Disadvantages of co-pitching
- If your pitch rate is off, you might overpitch and be left with an off-flavored product.
- Also referred to as the “kill factor”, when yeasts compete for the sugars, it can prevent one of them from growing, resulting in stalled fermentation.
- Sometimes, there’s no telling how the yeast will react. If fermentation goes wrong, it can be a waste of money, resources, and time.
Double Pitching Vs Co-Pitching – When Should You Do It?
There are some nuances to when you should use either method. The techniques often overlap. But here are situations that call for either of the processes. Here are examples of these instances below.
- When you have a stalled fermentation (when you’ve ruled out low temperature), you can add the yeast during the primary fermentation for dry fermentation.
- When the desired final gravity wasn’t achieved during the first pitch, you can pitch during the secondary fermentation.
- When using strains with different viable cell concentrations – to help the slow yeast convert all the sugars.
- To create enjoyable flavors. Co-pitching helps the yeast absorb more aromas from the remaining sugars.
- Similar to double pitching, you employ this technique when using strains with different viable cell concentrations. It helps one of the slower yeasts to convert all the sugars.
Double pitch and co-pitching are very similar techniques used in homebrewing and distilling.
Double pitching is often used when a fermentation hasn’t reached the targeted final gravity or when you have a stalled fermentation.
Conversely, co-pitching enhances the final product’s flavor.
But, some home-distillers have used double pitching to impart the taste of the yeast they’re using.
When co-pitching, it’s often preferred to use yeast with varying attenuation degrees. The second yeast helps restart the fermentation process when the initial yeast starts to stall.
If you decide to employ either technique, you must be familiar with the characteristics of your yeast.
Doing so reduces the risk of under or overpitching, which can be costly.
Double Pitching Yeast – Frequently Asked Questions:
Q1. What happens if you overpitch yeast?
Overpitching is far less of an issue that underpitching. If you exceed the pitch rate, you might wind up with an overpitched yeast. Overpitching can result in the following:
- A buildup of off flavors derived from diacetyl, sulfur, and fusel oil.
- Cloudy/hazy beverages.
- Meager ester production, resulting in a thin-body beverage.
Overpitching is irreversible. So you’ll have to discard the spoilt ferment and start a fresh wash.
Q2. When should I pitch more yeast?
Here’s when to pitch more yeast.
- When you’ve underpitched: Adding more yeast will ensure a dry fermentation.
- When fermenting at less than desired fermentation temperatures: Yeast is temperamental. Temperatures below “ideal” fermentation slow down the yeast’s ability to grow and ferment the wash till it reaches your desired final gravity target.
- When you have a stuck fermentation: Adding more yeast ensures you add some nutrients to feed the second yeast.
- When co-pitching: If you desire to create a fun flavored drink, you should add a strain with your preferred flavor profile.
Q3. How many times can you repitch yeast?
There’s really no limit, but you’ll be expending a lot of time an money for possibly not much gain.
We recommend you repitch yeast 3-5 more times before it loses its effect. Anything more than this, and you’re most likely to get a lot of bacterial load, a slow fermentation, and off-flavors. But experimentation is the name of the game. If you reuse yeast up to 5 times and are happy with the results, you’ll know where your preferred range is.