I suspect my starter tends to have a dominance of acetic over lactic flavour. Has anyone had success at increasing the lactic to acetic ratio?
There appears to be much conflicting information on this topic. I did find an interesting article on this topic. Here is a relevant paragraph from the article:
"Dough yield
Sourdough can vary in its consistency. The sourdough fermentation can be performed as firm dough or as a liquid suspension of flour in water. This proportion between flour and water is called the DY and is defined as:
The DY value of a sourdough will significantly influence the flavor profile of the sourdough. The firmer the sourdough (lower DY value), the more acetic acid is produced and the less lactic acid. The acidification rate is also influenced by the DY of a sourdough. The higher the DY, the faster the acidification will occur, most probably due to the better diffusion of the produced organic acids into the environment (Spicher and Stephan 1999)"
So it seems that a more hydrated starter will have a higher lactic to acetic ratio. Does everyone agree with this?
Incidentally the Spicher and Stephan reference appears to lead to "Handbuch Sauerteig", a useful looking tome except a) It's in German and b) It's extremely expensive!
Another way to increase lactic seems to be to ferment the starter anaerobically, as suggested in this article. But not so easy to do in the home (ferment under CO2 or at least in a sealed container to build up a CO2 pressure?)
Lance
Lance, you probably already know (but is worth a mention), acetic acid has a sharp vinegar like flavor and lactic acid is something like smooth and yogurt flavored.
Acetic acids like drier hydrations and cool temperatures. Lactic acids like warm temps and high hydration. According to my experience, a bread that has an intense lactic flavor can be produced by using warm (~77-79F) and very long fermentation. Maximum lactic flavor is produced by pushing the fermentation time to the very limits of dough degradation. If this interest you, let me know. I’ll send a link for an inexpensive online course that I took a couple of years ago. I have baked in excess of 200 of these loaves. Needless to say, I love this bread.
An opinion of mine (based on experience) is that the most important phase of building lactic acid in a bread is during the extended warm bulk ferment. I can very easily take a sweet starter (non-sour) and turn out a very lactic flavored bread. Keep in mind that only 2% of prefermented flour is used in the dough. This is what I think happens. Just like a starter left to over ferment turns highly acidic, so does the bread dough build huge amounts of acid during the long and warm bulk ferment. The dough acts exactly like a very large levain. Like stated above, dough degradation is the highest hurdle to over come. The qualities of the flour is super important for this type of bread. I am not scientific but my experience leads me to believe this.
Danny
Thanks Dan, I think I will initially play around with the two factors I mentioned, but, yes, warmer temperatures are also a positive. I build my levains at 27/28C, so I think I am already there with that variable.
Regarding lactic flavour description, I agree yogurt is a good pointer, but also think lactic pickles, such as sauerkraut straight out of the jar (or homemade!).
Or for some serious lactic, there are some beers that have this flavour. It used to be considered a fault in beer, but as with most things beer (like bread!), all the old rules have been broken, eg cloudy beer is now the norm. Guinness FES (Foreign Extra Stout) was brewed to have a strong lactic flavour, to be refreshing in hot countries such as Nigeria. I'm not sure what it tastes like these days though....
Lance
I use anaerobic and warm.
1st - anaerobic this way:
2nd - temperature-controled box:
I refere to this article and use for more lactic the range 90F - 32C and 93F - 34C.
To boost both, lab & yeast, I use the range for yeast, 79F - 26C and 82F - 28C, AND for lab 90F - 32C and 93F - 34C and switche between 79F - 26C and 93F - 34C.
The resulting curve is a saw wave!
Happy baking!
rudi
Thanks Rudi, great post. You beat me to it with the anaerobics! Though I might try a little CO2 blanket gas as well....
What hydration are you using? I'm usually on 80%, but I might try 125% for this experiment.
Lance
Hi Lance,
hydration:
for wheat (and similar)-sd from 60% up to 120%
for rye-sd from 80% up to 200% (two-h!)
CO2:
in the air we have 'only' 21% oxygen, so I dont worry much about in my 'anaerobic' environment!
yeast in sd may use this little bit, lab are oxy-tolerant and use the oxygen only as help for their metabolism -
see "Handbuch Sauerteig"! (yes, it's in my bookshelf! and yes, it's real great stuff!)
rudi