My sourdough starter is bubbling but not rising, suggestions?

If the starter is "bubbling nicely" then you may be already there.

Bread rises because the CO2 produced by the yeast is trapped by the protein in the dough. If you see bubbles then your starter is already producing the necessary CO2.

A starter has so much water in it that the protein doesn't trap the gas- thus you see bubbles rise to the surface. If you expect your starter to trap the gas and expand then it would have to have more protein. This isn't required for a starter to work.

You should be able to use the starter in a bread dough and that bubbling will turn into rising.

Sourdough is a combination of yeast (which provide rising power) and bacteria (which make the starter sour and keep other nasty things from growing in it).

New starters will usually establish strong bacteria growth long before they get strong yeast growth. The bacteria growth will start within the first couple days, which will make your starter begin to taste sour. Bacteria can produce bubbles too, but they produce so much acid on their own that the bread produced will not rise very well. With a starter that's only 4 days old and has only been fed once or twice, it's very likely that you're still seeing more activity from bacteria than from yeast. (Low temperatures, like those mentioned in the question, will also tend to favor bacteria growth over yeast.)

In my experience, it can take as many as 10-20 feedings with whole wheat flour to establish strong yeast growth, depending on your recipe. With rye flour, I've seen it in only 4-5 feedings under ideal circumstances.

In any case, the "bubbles" you see in a starter in the first few days are primarily produced by acid-generating bacteria. They help to make your starter more sour, which will keep other bad things from growing in it. That's the first step. The second step is regular feedings once the starter has some sourness. The feedings will dilute the acidity temporarily and allow yeast to establish growth.

I wouldn't expect much expansion on a newly cultured starter. Given the high water content it will be very 'slack'. Even my many generations old one doesn't rise much unless I leave it at room temp for an afternoon.

I would continue with the growth pattern you are following, i.e. cut it in half and feed again a few times. There would be no harm in taking the 'discard' each time and baking it up to see what you get. I'd make a simple starter-only loaf like the KA 'extra tangy' recipe and see what you get.

I created my starter 11/06/13. We've had a cold winter here in Connecticut. It took until after Thanksgiving for the starter to be ready to use in any baking. I arrived at this understanding through reading different posts on different websites and also the book I was using by Chad Robertson "Tartine Bread". In the book, he said it might be a matter of days to ripen and I began to think I might have killed it through some error. He did talk about placing a spoonful of starter in a cup of warm water and watching to see if it floats, floating starter in this scenario means it is ripe and ready to use!

I finally came across an article of a t.v.appearance he made where he revealed it could be a full month before one's starter is ready to use. I suspect with winter growing colder, adopting a clear feeding schedule, evening out how I compose the feedings, establishing a feeding time… this all sapped energy form my starter. Eventually, the starter was four weeks old and I was testing it each day. Finally, I could see the samples floating in the water when I would conduct a float test. Occasionally, I would come home from work and see it produced hundreds of bubbles over the course of the day as in the photo above… Give it some time!

I recently started a sourdough culture by mixing warm water with flour, incubating, and feeding it once per day for a week. I used it in a no-knead recipe, and it made a brick that had a few large air pockets but very few little bubbles.

I fed it again for a week and tried again, producing this:

It's a huge improvement, but there are still some very dense parts in the middle, and the loaf didn't rise much overall.

I'm going to keep feeding it and trying this recipe periodically. Hopefully it will improve with each iteration.

Yeah I've just started a new starter and am at the same stage. At the start of the week it was a very sour starter with some bubbles but little rise. I got some improvement when I started feeding it then putting it in the residual heat of the oven - long after i'd used it for cooking dinner and that seemed to promote more yeast action. My last starter took a month before it would be predictable.

Also, while your starter is getting settled. I recommend collecting the discards and making a a loaf with the help of baker's yeast - it gives you a lovely sour and light bread and softens the blow if your first few sourdoughs come out as bricks.

I've posted this as an answer to Techniques for making sourdough starter in cold/altitude but I think the warm water bath maybe the solution here as well. It certainly worked for me. I posted my 1st hand experience as a sourdough novice so that you can see if something similar happened to you.

I live in Richmond Hill just north of Toronto, Canada. The temperature in my house is kept at 18C (65F), and this is my 3rd attempt at making a sourdough starter with just water and flour. Two previous attempts failed probably because I was using just All Purpose White Flour and there was just not enough wild yeast in there. This time I used a 50/50 mixture of Whole Wheat with AP and I believe the wild yeast in the less processed WW made the attempt successful.

If you don't want to read the rest of the detailed post just remember the most important point is that in a cold room you need to put the starter in a warm 25C/75F water bath and re-heat the bath every 8-12 hours for the yeast to establish itself.

Day 1: 50g WW + 50g AP + 100g cold water that has been boiled.

Day 2: I see just a few bubbles, with a bit of sour smell.

Added 50g WW + 50g AP + 100g cold water that has been boiled (Nothing discarded, just double the weight)

Day 3: A lot more bubbles on the top but not on the side, very little rise in volume, with a very strong vinegar smell.

At this point I though that the smell is not right so I googled and found the answer right here in this thread. I realized that my room is so cold that it may take 11-18 days for the starter to form. I also read that different micro organisms in the starter thrives at different temperatures. Lower temperature encourages the growth of lactic acid bacteria (LAB) which produce acetic acid, which explains the strong acidic smell of my starter right now. What I want is more lactobacilli (which produce the milder, more pleasant yogurt like smell) and wild yeast. Lactobacilli thrives at higher (25C+) while yeast likes 21-25C.

So I split my starter into two jars. Added 100g AP + 100g cold water that has been boiled to each jar (nothing thrown away, and I stopped adding WW). I then filled a big stainless steel pot with hot tap water and added some cold tap water to bring the temperature to about 25C (I used a candy thermometer). I put the the jars in the water bath and left them in a cold oven. Before I went to sleep I re-heated the water bath to 25C again.

Day 4: Checked at noon and found that my starter is bubbling like crazy, success at last! The vinegar smell is now replaced with a milder, more pleasant sour smell. I added 200g AP + 200g cold boiled water to each jar, and re-heated the water bath to 25C.

Day 5: The starter is bubbling so vigorous that it has more than doubled in volume and oozed out of the jars. I am not ready to bake bread yet, so I stirred the jars down, took out a cup of the starter to make a very nice sourdough chocolate cake https://www.kingarthurflour.com/recipes/sourdough-chocolate-cake-recipe and put the two jars into the fridge for future experimentation.

Addendum:

Today I baked my firsts sourdough loaves. Turned out pretty well. Not much sourness, which is good. I tried using the https://www.karenskitchenstories.com/2016/08/sourdough-hokkaido-milk-bread-with.html recipe, using only about 60g of starter from the fridge mixed with 60g of water and 60g of AP flour to triple it. But after a few hours there was not much activity. Tried putting it into the oven but I may have turn the heat up too high and since there is not much flour/water mixture there I may have killed the yeast. So I abandoned the recipe, took out another 100g of starter from the fridge and added 100g of water + 100g of flour and left it overnight. The next morning I can see bubbles so the yeast is alive but not vigorous. So I took the pot to my room where it is sunny today and left is sit there for about 4 or 5 hours. It became very bubbly (I have 600g starter, so othat is 300g flour + 300g water) and I mixed in with 5 cups of flour along with my tangzhong made with 1/3 cup flour + 2/3 cup water. I also added 1/4 cup Crisco oil with 6 TBSP of sugar. I kneaded it and added just enough water to make a smooth dough. I let it ferment for about 10 hours for the volume to double. Then I gently shaped the dough into 3 loaves, and left them in the cold oven overnight. The loaves have double in volume in the morning and I baked them straight away. The crust was not bad and the texture is quite nice. So sourdough starter can definitely rise the dough twice.

So the lesson here is that you need to make sure the starter is tripled under warm conditions (21-25C). The best way to do that is by using a water bath (hot water from faucet mixed with some cold water) and then leave it in the oven (without turning on the oven, of course). Maybe a good idea for you to get a cheap candy thermometer to make sure the water is not too hot. You also need to give the starter enough time to ferment. The final dough also needs at least 12 hours to rise properly.