Growing Natural Yeast (using grapes) 葡萄天然酵母

Bread baked with the addition of poolish dough using natural yeast has a nicer aroma, finer and more springy texture, as well as having a more moist crumb. The softness of the bread can last till the 4th day. 

This is a sharing of my more successful experience in cultivating natural yeast for baking use. I have failed thrice using just water and flour. My previous cultivation though successfully allowed me to bake a nice loaf of bread, I think I have over extended the cultivating period. Unless you have seen the entire phrase of the cultivation, you could not judge when is the right time to transfer or "harvest" the yeast. 

With the detailed documentation, hope it would helps new natural yeast "farmers" like me to have a better picture of the entire process. This is not a guide book, just an experience sharing.

Good luck 👍🏼🍀

Getting started...

Equipment & Ingredients

1 glass bottle with lid, about 600~800ml

200g fresh grapes

200g cool boiled water

50g raw/fine sugar

Directions 

1. Rinse the bottle with boiling water to sterilize it. Allow to dry before use. 

I kept it in a warm oven.

2. Rinse and drain the grapes. Slice the grapes into halves.

3. Place all the ingredients into the cool sterilized bottle, and cover with a lid. 

Avoid over-tightening the lid, just loosely close, so pressure would not build up in the bottle.

4. Swirl the ingredients a few rounds to mix the ingredients.

Open the lid once every day and give the ingredients about 2 to 3 swirlings each day. So oxygen can circulate in the liquid.

5. Label date on the bottle for record purpose. Keep the bottle in a cool place. See you the next day 🌻

Day 2 (1.12.2015)

Temperature: 27 degree Celsius

Feeding: no

Observation: a little bubbles can be seen.

Day 3 (2.12.2015)

Temperature: 27 degree Celsius

Feeding: no

Observation: a lot more bubbles can be seen. A faint alcohol smell can be detected.

After swirling, more bubbles have been released.

Day 4 (3.12.2015)

Temperature: 27 degree Celsius

Feeding: no

Observation: Bubbles have reduced drastically. Time to transfer.

There are more bubbles after swirling. It looks and smell like beer 😄

Poolish Starter

Addition:

100g natural yeast water

100g unbleached bread flour

Directions

1. Filter out the grapes and transfer the yeast water to a glass jug.

2. Pour 100g of yeast water to a cool sterilized bottle.

Pour 100g unbleached bread flour into the bottle.

Stir to mix.

3. Loosely cover with a lid. Mark the level of the poolish starter with a rubber band. Label the date and time for monitoring purpose. See you later.

Storage - yeast water

For the remaining natural yeast water, seal in a sterilized bottle, label with a date, and keep in refrigeration.

Label the natural yeast with a date sticker.

Refrigerate it. The references I have read indicated the yeast water can last about a week or more in refrigeration.

Poolish Pre-ferment 

Continue with the poolish starter from above.

Day 1  ( 3.12.2015)

Temperature: 27 degree Celsius

Feeding: no

Observation: the poolish dough raise to about 4 times the original height. The natural yeast is very active.

Beginning 

1 hour 20 minutes later, the volume has almost double.

2 hours 20 minutes later, the volume has increased more than double.

The poolish dough almost filled the bottle up to the rim by end of 3-hour fermentation period. The yeast is very active and is ready to join the baking ^^

4 hours later, the poolish dough starts to reduce in volume slightly.

As I would only bake in the next day, so 8 hours after the fermentation started, I kept the poolish dough in the fridge till 1am. I took out the poolish dough before I went to sleep, to let it return to room temperature. So I could activate the natural yeast when I woke up the next day.

Day 2  ( 4.12.2015)

Temperature: 28 degree Celsius

Feeding: 10g water & 10g bread flour

Observation: the poolish dough double after feeding within 2 hours. It is active and suitable for baking.

The poolish dough before feeding.

After the feeding, close the lid, mark the dough height with a rubber band, and label the time.

After 1 hour, the dough raise to about 1/2 the original height.

The dough raised to about double the original height after 2 hours.

110g of the poolish dough was harvested  and use in baking of soft white bread.

Click the link to the soft white bread recipe:

http://mymindpatch.blogspot.sg/2015/11/easy-kneaded-soft-white-bread.html

Storage - poolish dough

For the remaining poolish dough, if you want to bake in the next day, add an equal weight of water and flour to the poolish dough, to start another round of cultivation.

If you have no plan to bake in the next two day, you can keep in a clean and sterilized container. Mark the date and refrigerate it.

Restoring the natural yeast 

To re-activate the sleeping yeast from "hibernation".

1. Allow the cold poolish dough to return to room temperature.

2. Add an equal amount of water and bread flour to the poolish dough. For example, 20g poolish dough/natural yeast + 100g cool boiled water + 100g unbleached bread flour.

Below demostrstion only used a small amount of water and flour to reactivate the natural yeast, is for testing purpose only.

1 hour after feeding, the volume has double. Therefore, the natural yeast is healthy and active to be engaged in the baking *\(^o^)/*

Restoring long inactive natural yeast

If the natural yeast has been kept inactive in the fridge for over 2 weeks, a film of yellowish liquid will develop at the top layer.

You will have to discard the yellow liquid and only keep part of the old natural yeast, then start a new batch.

Direction 

1. Allow the cold natural yeast to return to room temperature.

2. If the natural yeast has been inactive for too long, a layer of yellowish liquid will form at the top. Pour away this liquid before feeding your natural yeast.

3. Collect about 20g of the old natural yeast, and transfer to a new sterilized container.

4. Add an equal amount of water and bread flour to the natural yeast. For example, 20g natural yeast + 20g cool boiled water + 20g unbleached bread flour.

Stir, cover and mark by a rubber band. 

Label and wait for the natural yeast to double in volume....

After 2 hours, the natural yeast only climbed to about 1/4 of the expected height. The rate was slow at room temperature of 29 degree Celsius (ｰ ｰ;)  

After 4 hours of wait, the natural yeast finally reached the double volume mark

 *\(^o^)/*

At this slower than usual fermentation rate, it is best not to use the natural yeast, but give it a few more days of feedings, till the rate returns to normal - double within an hour.

On my second feeding on the third day, the natural yeast has regained its strength and double within an hour 

*\(^o^)/*

The natural yeast is ready to work again :)

Topping up with yeast water

While feeding the natural yeast, you can use the yeast water you have stored in the fridge instead of using plain water. This helps to inject the nice flavour of the grape, which gradually diminished after a few feedings by water, back to the yeast.

Before adding the yeast water, swirl the bottle a few rounds. If the yeast water becomes foamy, it is a good sign that the yeast is healthy. If the yeast is lifeless, it's about time to let it go and keep a new batch.

Directions 

I replace half of the feeding water by the yeast water.

For example,

Natural yeast poolish dough: 100g

Yeast water                         : 10g

Cool boiled water.               : 10g

Unbleached bread flour.      : 20g

Total                                  : 140g

Collect 100g of natural yeast,

add in 10g of yeast water, 10g of cool boiled water, and 20g of unbleached bread flour,

Stir to mix into a smooth paste.

Cover with food wrap and a lid. Mark the new natural yeast height with a rubber band. Wait for the natural yeast to raise to double this height. It only took 1 hour to reach the new height.

It's useful to keep a record of the feeding quantity, date and time in a small post-it-note. So you'll have an idea of the quantity of the content, as well as the "production date".

Keep the new lot of natural yeast in the fridge, if you want to stop baking for more than 2 days. 

Otherwise, you can keep it in room temperature, and do the daily feeding.

Renewing Natural Yeast

A bottle of natural yeast which has been fed several rounds may become increasingly sour. This will cause your bread to become sour too. When the sourness of the natural yeast is getting too high, the yeast will become less active despite your regular feeding.

To overcome this, you'll have to discard part of the natural yeast, and keep a small portion to re-cultivate it into a new batch.

For example, 

Keep 20g of the old batch of natural yeast and discard the rest.

Then add 10g each of water and bread flour to form a new batch of 40g of natural yeast.

Let the natural yeast to double itself to check the activeness of the new batch.

Keep the natural yeast in room temperature if you're going to bake in the next day to two. Or else, keep it in the fridge.

Happy farming :)

Reference :

http://lindawu122470.pixnet.net/blog/post/175000689

http://stepwongkitchen.blogspot.no/2014/01/blog-post_20.html?m=1

http://caroleasylife.blogspot.sg/2013/12/nature-yeast.html?m=1

and 

with appreciation :)