Trine Hahnemann sourdough rye bread. Is this underbaked or some other problem?

Trine Hahnemann sourdough rye bread

After baking the bread has large patchy areas that are “gummy, wet/slimy, and seem to be underbaked.

I have made this bread from scratch before (in 2019), it was good and I successfully kept back some starter and used that to make several loaves over about 2 years. All of them worked very well. The bread is dense tastes great and keeps for longer than a week on the bench top. But then stopped and discarded the starter. The starter was never hugely active and bubbly. I think that is the nature of this sourdough starter.

I made a new starter (using milk and some lemon juice and a little plain “Greek Style” yoghurt in lieu of buttermilk) over about 4 days. The room temperature was about 19-21C so during the last 2 days I put the started in a warm oven around 25C for a few hours).

 The starter had a few bubbles, it did not smell bad/rotten.

I followed the recipe which can be found online (here is one site):

https://www.souschef.co.uk/blogs/the-bureau-of-taste/rye-bread-recipe?srsltid=AfmBOoqwME5yNjSN3J3Lc_rHUXCDklGRGh59h8GsTa_Zt8YKCAdUGgnd

Ingredients for the rye sourdough starter

300ml buttermilk

300g wholegrain stoneground rye flour

For the rye sourdough starter, mix the buttermilk and rye flour well in a bowl, cover with a tea towel and leave at room temperature for 3 days, ideally at 23–25°C (73–77°F). It is important that it doesn’t develop mould, but it should start bubbling.

Day 1: If you’re making your first loaf from the starter, dissolve all the starter in the lukewarm water in a large mixing bowl (for subsequent loaves use just 3 Tbsp of the starter; see Day 2, below).

How to make rye bread

Day 1

sourdough starter from above

850ml lukewarm water

15g fine sea salt

750g wholegrain stoneground rye flour

Stir in the salt and rye flour, cover the bowl with a tea towel and leave at room temperature for 12–24 hours.

Day 2

500g cracked rye

250ml cold water

A little flavorless vegetable oil, for the tin

Day 2: Add the cracked rye and cold water to the dough and stir with a wooden spoon until smooth (it will be too runny to knead).

 Remove 3 tbsp of the mixture to an airtight container and refrigerate; this will become your sourdough starter for the next loaf you make. It will not need taking care of, but it will need to rest for at least 3 days before you use it again. It will last up to 8 weeks.

Lightly oil a large loaf tin, about 30 x 10cm [12 x 4in], and 10cm [4in] deep. Pour in the dough, cover with a damp tea towel and leave to rise at room temperature for 3–6 hours, or until the dough has almost reached the top of the tin.

When ready to bake, preheat the oven to 180°C/ 350°F/Gas 4. Bake the loaf for 1 hour 45 minutes, then immediately turn the loaf out of the tin on to a wire rack to cool. 

Just before removing from the oven the Internal temperature of the bread was >97 degrees C.

 I allowed the bread to cool for >20 hours before slicing.

1.       Any ideas as to what went wrong and why?

2.       Should I try again using the reserved starter (which I kept as per the instructions) or should I start from scratch again?

3.       Can I do anything with this loaf, like try to dry out in the oven, or something else?

Thanks for your comments