Mountain Maiden asked me how to make whey starters in a PM and I thought this is a question that many people have wondered about. Specifically, before modern microbiological practices and the convenience of freezers, what did people use for starters, and how did they maintain quality?
There's a decent thread about clabber already, so I will focus on thermophilic starters here. For farmstead people and traditionalists, especially ones who have cows and not goats, thermophilic whey starters are a good approach because it is easier to maintain cleanliness due to the inherent ecosystems involved and the thermizing step in making and maintaining the starters.
The tradition of whey starters goes back many centuries, and is perhaps 3,000 or more years old. The areas that have used whey starters tend to be in a Mediterranean climate, especially what is now Italy, and going up from there into the Pyrenees on the west and the Jura region on the east. Many famous cheeses rely on whey starters, including Parmeggiano-Reggiano, alpine types (gruyere), and the many thermophilic variants found in the general region.
Tradition has it that whey starters are something special passed down among generations learning the art, and that when a new maker began, it is of crucial importance that a master transfer an established starter to a new location. The variety of microorganisms in starters contribute to regional variations in flavor and characteristic cheese aroma, taste, and texture.
All this begs the question that someone somewhere must have done it originally, and that not all whey starters were transferred from a single genius who invented the process. And this is quite right. In fact, it is relatively straightforward to create your own whey starter and stabilize it for use.
First, a primer
- Whey starters contain predominantly thermophilic bacteria consisting of strains from the lactobacillus and streptococcus genuses. Often, they contain multiple strains of L. helveticus, L paracasei, L. delbrueckii ssp., L. acidophilus, L. casei, L. plantarum, etc.
- The variety of flora is obtained over time until the strongest bacteria that can survive the harsh acidic conditions of whey predominates and forms a stable ecosystem.
- A stable whey system is very resilient to contamination, provided that it has a chance to respond to stress and adapt to the new situation. It vital, therefore, in whey systems, to be as repetitive as possible in maintaining conditions
- Bacteria in whey systems, because of their complexity, tend to be fairly phage resistant.
- To maintain whey starters, it is crucial to create conditions that favor the growth of thermophilic bacteria
- It is possible to keep a whey starter and not use it immediately the next day, but it decreases consistency
1) Take fresh, raw milk and heat it to a temperature of 125F. Maintain this temperature for 20-30 minutes. This kills mesophilic bacteria and common pathogens, but does not kill off resilient lactobacilli.
2) Cool milk down to a temperature of 110-115F. Keep it there until the milk coagulates. This may take several days. Keep in a closed container. Traditionally, this was accomplished by natural means, such as taking an earthenware/clay container, and setting it outside in the hot summer sun where it would remain at a constant temperature suitable to the growth of thermophilic bacteria.
3) When the milk coagulates, retain 10% of the volume, and use the rest. Feed to the animals, strain for a lactic cheese, use in cooking, etc.
4) Begin the process in step 1 again. When you arrive at step 2, add the retained, coagulated milk from the previous batch and add to the fresh milk when the temperature is 110F-115F. You are now selectively inoculating the next batch and concentrating the native thermophilic bacteria in your environment.
5) Repeat this process 7-20 more times until you can achieve consistent results. Meaning the curd looks the same (like yogurt), tastes the same, has no off-smells or flavors, etc. It is crucial to repeat this process to obtain a stable culture.
6) When you are happy with the batch, make a very basic hard cheese following a thermophilic recipe, such as for parmesan. Use the culture as your inoculant at a rate of 5% (for the first cheese). When you strain the whey, retain it.
7) Take the retained whey and keep it at 105F until the next day. The next day, make the same cheese, using 2.0%-2.5% starter. By now, the starter should be active, stable, and consistent. For a pH quality control point, the starter should be about 4.0-4.2 when you add it. It could be a little lower or higher, but not much.
8 ) Retain the whey from the second batch and the next day, use it for a third batch.
9) Repeat the batches another several times, until about a month has passed from when you originally started at step 1. By now, there have been many generations of bacteria, and they will have formed a stable ecosystem.
At this point, you can use this whey in place of any thermophilic starter. This process does not always work, and tends to work best during the summer. If you make a particularly good batch of starter, be sure to retain it and use it for the future.
To save starter:
- Freeze the whey in a bag or ice cubes
- If using within several months, use as is at a rate of 1.5-2.5% by weight (depends on the cheese and recipe, and the starter acidity curve)
- If reconstituting saved starter, start at step 1 and go through several generations of propagation without making cheese, until the culture is stable again.
With this method, your starter will produce very similar cheese in taste regardless of the recipe you use. For example, a parmigiano-reggiano clone will be somewhat similar in taste to its northern cousin, Montasio. This is because the strains of bacteria are predominantly responsible for the flavor.
If you have any questions, please post. Sorry, don't have pictures.