Xbeeriment with sourdough yeast
I love to experiment with food as is clear from my other blogs. A couple of weeks ago this turned to beer. Here’s how it unfolded. I’ll also apologize in advance here. Brewers are going to know what I am on about here. The rest of the world not so much.
A month previously I was making a stout, and it stalled out at 1.024. If you’re a brewer you know that this is not good news. Your yeast stopped doing its thing, well before all the sugars were fermented. Once that happens there is not a lot you can do about it. But I did. I pitched some sourdough starter in it thinking ‘what have I got to lose?’ It turns out plenty. The sourdough did a great job of fermenting the brew right down to 1.003 which means a that just about all of that sugar got fermented. However on the way, it also changed it to vinegar. Perhaps someone could be generous and say that I now have a sour stout. But really. Don’t think so. As beer vinegar its good – all 6L of it.
But I wanted to explore further what the effect of sourdough would be on fermentation if I used it uniquely. I had no idea what it will turn out like once its been in the bottle for 6 weeks.
I decided I would make a brew and split it in half to pitch the yeast. One would get SD and the other would get sourdough. As for the grains, truth be told I was at the end of my supply and needed to use stuff up. That is why the quantities are a little strange
Here is the recipe that came about:
This is for a 6 litre batch
11 litres of water
.81kg Maris otter
.2 kg White wheat
50g Caramel 20
14g Tettnang (17.9 IBU)
- ½ the batch received sourdough: 200g very active SD yeast was pitched in 400g 1.035 wort about 10 hours before pitching
- ½ the batch received 2.4 g of Lallemand Belle Saison, hydrated for about 30 minutes in RO water.
My process was pretty simple BIAB:
- 11 Litres of water in a 20L tun
- BIAB full body for the mash. Strike temp: 74.4C; Mash 68.9C 1 hour; mash out 15 minutes to 75.6C
- Add Tettnang at the start of the hour boil
- I should note too that I’ve come to like using a fairly heavy boil which yields a crazy high OG, and then I use ice cubes to bring it down to the desired 1.060 OG
Usually I use the same 11 L container I measure and pour the initial water from as my fermentation vessel. This time, I used 2 gallon cider jugs. The SD refresh was pitched in one and the Belle Saison in the other.
Here are my observations at bottling:
|FG||1.010 (ABV 6.6)||1.011 (ABV 6.5)|
|APPEARANCE||Darker, clearer, a lot more trub, bits of flocculant on the top||Lighter, cloudy, more settled, a lot less trub|
|TASTE||A good slightly hoppy ale – slight floral and spice notes||A more neutral ale but there is a hint of sourness (which makes sense – SD has lots of lactic acid bacteria)|
|Total volume at bottling||5.75 L||6.25L (there was that much difference in the trub.|
Some interim conclusions and next steps
- I’m really delighted both brews worked themselves down to 1.010. I must be doing something right.
- If my beer yeast were to get destroyed, I’d still be brewing
- I’d like to see the effect of changing my hops – what would a low IBU and a high IBU similar experiment yield? I have heard that hops tend to destroy the LABs so perhaps really low IBU may result in a sour beer
I will finish this blog in 6 weeks when I taste the final product!