I'm wondering if anyone out there has a document or knows of a good online resource that outlines the full temperature ranges (and ideal ranges) of all the different strains of bacteria in both meso and thermo starters? I know that each strain within the starter mix has its own characteristics and temperature ranges that overlap slightly. The documentation that is provided usually specifies an averaged range for the packet as a whole, but I'm looking for specifics as each strain adds a different characteristic.
ideal and range for what? For propagation, or rate of lactic acid production, or fission for colony growth or what?
linuxboy,
I assuming one comes with the other. In ideal environments, they eat, reproduce, eat, reproduce. If the environment is less than ideal they go dormant.
When added to the milk at a given temp in a recipe they are doing both, at a rate being controlled by time and temp. Would you agree? If not, please explain. (It's been 20 years since I've had a microbiology class)
Since there are varying definitions of ranges published on the Internet for both categories of bacteria, I'm wondering if there is something that lists the usable temp ranges for dairy specific bacteria that come in starters that you buy from the major home cheese making suppliers. The ranges on the labels define the approx ranges for the blend as a whole, but specific strains inside that blend may have the capability to thrive in higher or lower temps outside that range. I'm interested in figuring out what that is, by strain.
QuoteI assuming one comes with the other.
Kind of. Bacteria have 4 distinct phases
1) Lag phase - when DNA is replicated, but there's no colony growth. There's metabolysis, but no multiplication
2) Log(exponential) - this is active colony growth
3) Stationary/maintenance - death rate equals multiplication rate. waste accumulates.
4) Death - death rate exceeds multiplication rate. Usually, osmotic pressure, waste, pH are not favorable.
You can tweak all the phases through temp variations. A lag phase will grow better at the mid to higher end of the range, and a log phase will grow better at the higher end, and the death phase will do better if you cold crash it.
Quoteat a given temp in a recipe they are doing both, at a rate being controlled by time and temp
That's true. And if you're culturing individual strains, you can keep the temp constant. But here's the rub - most bacteria have multiple metabolic pathways. They will produce different byproducts based on the food source and the temp. For example, heterofermentive lactic bacteria will produce diacetyl and acetic acid, among other things (like CO2). But, the rate of production of those byproducts is very temperature dependent.
QuoteI'm wondering if there is something that lists the usable temp ranges for dairy specific bacteria that come in starters that you buy from the major home cheese making suppliers
Usable for what? If you want to set it and forget it, it's:
85-88F for lactococcus
100F for Streptococcus
72-75F for heterofermentive like leuconostoc
105F for lactobacillus
If you want to go strain-specific, you have to look at the published studies, and the information about commercial varieties are largely unpublished, although you can extrapolate.
If you have a question about a specific culture or blend and want to know ranges, let me know. No time to write more right now.
Good info.
QuoteFor example, heterofermentive lactic bacteria will produce diacetyl and acetic acid, among other things (like CO2). But, the rate of production of those byproducts is very temperature dependent.
This is similar to yeast in beer. I need to research more to figure out which byproducts produce certain flavor characteristics that I'm interested in (i.e. diacetyl imparts a buttery flavor)
I have homework to do.
leuconostoc and l. lactis diacetylactis produce diacetyl. Yes, very similar to yeast. The rate of diacetyl production, for example, is temp-dependent in bacteria.
most metabolic-flavor characteristics only apply to fresh cheeses. You do get some volatile formation with these byproducts, but the vast majority of the flavor in cheese is not due to the metabolysis or products of it, but due to the endo and exo peptidases and proteases.
If you're interested in specific flavors, let me know and I can help pick out strains. Picking strains based on metabolic byproducts for anything other than fresh cheeses will not result in very distinctive flavor formation. This is for lactic bacteria. If you wanted to, you could co-culture with other bacteria to try and create flavors, but usually it's easiest to select strains for endo and exo peptidases and proteases like I mentioned.
Snipe, beyond academic curiosity, what exactly are you trying to accomplish?
There may be an "optimal" temperature for a bacterial strain to produce diacetyl, for example, but that doesn't necessarily mean that it's the optimal temperature during a cheese make. It's NOT just about the bacteria. There are tons of other interrelated processes going on that have to work together as a whole. So just because lactobacillus are "optimal" at 105F doesn't mean that you ripen the milk at that temperature. In fact, very often you don't even want optimal conditions. Rapid acidification for example can lead to bitter peptides. Slow and steady wins the race.
And given that a lot of activity happens during and after pressing, you certainly wouldn't want to age a cheese at higher temperatures just because one bacteria like that temperature. So strains are partly chosen for their long term aging properties, not just for how they act for a few hours during the initial make.
Not to hijack, but I'm thrilled to see this post. This is EXACTLY the type of info I've been thinking about for a few weeks. I'd like to know optimal temperatures to incubate my mesophilic and thermophilic primer cultures (https://cheeseforum.org/forum/index.php/topic,5165.msg38655.html#msg38655) overnight. Ricki Carrol says 72F (meso) in her book, but seems like optimal growth/acidity temps are higher than that.
I've been reading a lot of different sources that have rather widely varying advice:
-CHR Hansen recommends incubating mesophiles (including Flora Danica) at 95-113F in their product spec sheets in the Library (https://cheeseforum.org/forum/index.php/topic,2967.msg24197.html#msg24197)
-my various other internet research (journal papers and websites, eg Dairy Connection (http://www.dairyconnection.com/cultures.jsp)) suggests:
77-86F generally for mesos,
64-77F for "aromas" like Lactococcus lactis biovar diacetylactis and Leuconostoc mesenteroides subsp. cremoris
104-110F for thermophiles like S. thermophilus (higher end of that for bulgaricus)
I also gleaned from somewhere that ideal temp for acid production is 2-8 degrees Celsius higher than optimal temp for growth. This got me started thinking about what Sailor and linuxboy are clarifying in this post- there are more variables that play into incubation temps than I thought. It makes it much easier to understand why ripening temps are all so different in various recipes.
So to end with my question: (CheeseSnipe, I hope this is adding to the discussion and not distracting to your original thread...)
If I want to incubate a meso primer culture overnight (~8hrs) using a typical starter like L. lactis +L. cremoris, what temperature would be ideal?
For thermo there seems to be general agreement that 110F (to grow overnight primers) will do the trick.
For ripening temps, I'm just going to follow the darn recipe and not think about it too much... for now...
QuoteRicki Carrol says 72F (meso) in her book, but seems like optimal growth/acidity temps are higher than that.
It's not wrong per se, but 72 is the ultimate meso safe harbor temp regardless of the culture strains and types. Suboptimal for common O culture.
QuoteCHR Hansen recommends incubating mesophiles (including Flora Danica) at 95-113F
Typo, that's the range for thermos. FD especially is incubated at max 75 F. I like 74F.
Quote77-86F generally for mesos,
64-77F for "aromas" like Lactococcus lactis biovar diacetylactis and Leuconostoc mesenteroides subsp. cremoris
104-110F for thermophiles like S. thermophilus (higher end of that for bulgaricus)
Correct, that's the proper range.
Quoteideal temp for acid production is 2-8 degrees Celsius higher than optimal temp for growth.
Yes, acid production is faster at higher temps.
Quoteusing a typical starter like L. lactis +L. cremoris, what temperature would be ideal?
O type culture is at 85F.
QuoteFor thermo there seems to be general agreement that 110F (to grow overnight primers) will do the trick.
Eh, that's too high for me. I do 100F, max 105. Thermos have a WIDE range of temps. You wouldn't use 100F with some Streptococcus and some helveticus, you'd use 95F. Might be okay for some strains of Helveticus. I like my helveticus at 98-100F, especially helveticus used as adjunct.
Here's the other part of this. Bacteria will change based on the temp. Meaning if you culture and grow a O type culture (lactis and cremoris) at 80F, but then make cheddar with it, and your cheddar is cooked to 102F, and you add the culture at 88F, you just grew an entire population at the lower end of the range, and then push it to perform at the higher end of the range. Not optimal. Your bacteria will be stressed. It is used to a mild temp, and then you stress the heck out of it right away. Your lag period will be suboptimal, and your population growth and acid production will be NOT what you expect. For this reason, it is usually important to culture close to the relative temps of your make. That's why the range you posted works. You use something like 76-78F for a chevre frais, and you culture FD or similar heterofermentive culture at 76F. You add culture for most continental cheeses at 88-90F, and so you culture the meso at 85F.
Thermos are a little different in that you actually want thermos to build acid slowly, and grow more in the starter, that's why you propagate at 95-105F, and then also add the mother at ~100F.
There's a lot to this. That's why I keep requesting specific questions about specific cultures; too much to type otherwise.
There are practical considerations in a daily cheese making environment. I do my MCs near the end of the day and incubate mesos overnight at room temp, around 70F. Ripening at a moderate pace means that the cultures are perfectly ripe by mid-morning and ready to use fresh if I want. I have tried higher temps (85F) for mesophiles and I find that the MCs are past their peak by the next morning. So, that overnight duration from 5:00 p.m. to 9:00 a.m. (16 hours) is too long at 85F and the acidity builds up too much. If I make them early in the morning it takes 1-1/2 hours or more to heat sterilize the milk and then cool down naturally. So the 6 hours remaining in a work day is not enough time. Yes, you can control acidification rate somewhat by using less bacteria to start with. However, using less starter for your MCs also increases the risk that contaminants can take hold.
The problem, IMHO, is that there is no perfect "ideal" temperature for a mixed strain culture because various bacterial strains have individualized optimums. No mater what you do, one strain or another will reproduce faster than the others. That's exactly why I don't use the current MC to inoculate the next MC (like yogurt). So, the only way to really obtain "perfect" conditions would be to make MCs of each strain individually. Incubate one at 80F another at 84F a third at 92F. Then add varying proportions of each to the milk as a blended starter. Not a bad idea really, if you have an on-site lab and can pull that off. After all, custom mixes with proprietary strains and secret proportions is what a DVI culture is anyway.
Quoteculture close to the relative temps of your make
Meaning, culture primers/mothers at a temp similar to that first ripening step of the make recipe (do I have to look at later curd cooking temps too?)
What I think this all means for my very small scale/hobby situation is:
I'll try to make my primer incubation temp match my recipe ripening temp (within say 2-5 degrees F), and generally follow the temperature guidelines we've discussed here. I'll also need to figure out how this works with the timing of my primer/mother culture method; my overnight incubation is closer to 9 hrs (since I'm doing this at home, 10pm-7am) and I'll need to see where the cultures are in the morning if they spend those 9 hrs at 85F, vs 80F or whatever...More experimenting to do. ;D
It's rather interesting to think about what I've grown in my first try with primer cultures, incubating L. lactis + L. cremoris for 10 hours ranging from 85F down to probably 60F overnight (terrible job controlling temp this first time)... but whatever I grew it did make a Gouda! (My plan for temp control next time is a 3-setting heating pad controlled by a digital thermostat, maybe in the oven or in a cooler. We'll see.)
Like usual, it seems I've gotten ahead of myself in digging into complexities before logging enough flight time. I think I'll relax and go with this for a while, until I've made more varieties of cheeses, and expanded my experience with different DVI mixes. Thanks for all this clarification- makes more sense why it's so hard to find information on incubation temps (because there is no one-size-fits-all answer). :D THANKS