Author Topic: Weighing DVI starter cultures  (Read 378 times)

Offline Bear and Bunny cheese

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Weighing DVI starter cultures
« on: April 08, 2014, 09:17:10 AM »
Hi gang,
  Been a quiet lurker here for a few years and I have had many questions about cheese making that I easily find answers for by searching this site, up until now.  So much knowledge here it`s incredible!  So, I`ve been working hard on keeping pH targets exact with my pH meter to fix some overacidification problems and amongst my attempted remedies is to be more precise with the amount of starter culture I use.  Instead of using tiny measuring spoons I have bought a micro scale (precision to .1 of a gram).  Problem is I cannot find any recipes that use weight for measuring cultures.  Is there a guide anywhere that explains how much 1/16th , 1/12th etc. of a teaspoon is in weight?  I use DVI starters exclusively and wish to continue doing so. My make size is 14 -16 liters of milk.  Thanks very much for any help you can offer.
Nathan
 
Nathan


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Offline jwalker

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Re: Weighing DVI starter cultures
« Reply #1 on: April 08, 2014, 09:41:25 AM »
I don't know if there is such a table available as most cultures would have different weights per their mass , especially taking any moisture into account , but if their was one , Linuxboy would probably know.

I don't think it's even that important to be quite that precise with starters anyway , sometimes they have to be adjusted for age and such.

I've also tried a micro scale , and with some cultures , the amount needed was less than 1/10th of a gram , so the scale wasn't much help anyway.

Hopefully someone else will have some more info for you.
No..........I'm not a professional CheeseMaker , but I play one on TV.

Offline ArnaudForestier

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Re: Weighing DVI starter cultures
« Reply #2 on: April 08, 2014, 10:39:58 AM »
Hi gang,
  Been a quiet lurker here for a few years and I have had many questions about cheese making that I easily find answers for by searching this site, up until now.  So much knowledge here it`s incredible!  So, I`ve been working hard on keeping pH targets exact with my pH meter to fix some overacidification problems and amongst my attempted remedies is to be more precise with the amount of starter culture I use.  Instead of using tiny measuring spoons I have bought a micro scale (precision to .1 of a gram).  Problem is I cannot find any recipes that use weight for measuring cultures.  Is there a guide anywhere that explains how much 1/16th , 1/12th etc. of a teaspoon is in weight?  I use DVI starters exclusively and wish to continue doing so. My make size is 14 -16 liters of milk.  Thanks very much for any help you can offer.
Nathan
 

Bear, it's a bit cumbersome, but you'd have to see how many DCUs per weight there are in your particular lot, of your bought culture.  E.g., say it says 50 DCU, 25 g pouch.  You now know you've 2 dcu per gram.  Each culture, even each lot of each culture, is different - one pouch of culture x might say 50 dcu and 25 grams, another of the same culture but a different lot might say 50 DCU and 22.3 grams.  It's to do with the manufacturer's voodoo on "acidifying strength" of each lot number.  More complicated, but it's enough to know the pouch DCU and weight (some don't give you that - just the DCU and/or dose; you'd have to find the net weight of the pouch, to figure the DCU per gram....more of a pain).

There's a conversion of mother cultures in bulk, danisco and CHR Hansen somewhere on this site - sorry, I've lost track.  But as a for instance, say you would like to do a 1% bulk equivalent of starter (bulk equivalent meaning, if you were doing this with bulk culture, you'd be putting it in at 1% v/v).  Let's say you were doing a 4 gallon batch, 15.1 liters.  1% by volume would then be 151 milliters.  The equivalent, given in this chart, of Danisco DCU (at 1% bulk equivalent) would be .98 DCU.  So, knowing your culture comes in at 2 DCU per gram, you would use .98/2 or .49 grams culture. 

You might want to double check me on this - I am prone to spacing if I don't slow down, but I believe that's correct.  Let me know if you can't find the chart I'm talking about, I believe Sailor Con Queso kindly provided it on one of his threads (look up "mother and DVI culture  calculation"), and Sailor or Linuxboy are the go-to guys for this stuff.  I think it checks out, though, and in the event they didn't get back here soon, wanted you to have something.  Good luck. 

- Paul

Offline Bear and Bunny cheese

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Re: Weighing DVI starter cultures
« Reply #3 on: April 08, 2014, 05:44:24 PM »
  This is such great information!  Just what I needed to know.  Thank you so much Paul! I humbly bestow my first cheese to you for this.
  So is DCU (Danisco Culture Units) a test of cell viability, or the overall acid producing ability of the culture (or something else)?  If it is viability then I would assume it's potency would go down with time and storage integrity, humidity pickup etc.
  I would expect that the culture producers would label the DCU number at the point of manufacture assuming that it would be used all at once by a big cheese manufacturing outlet.
Nathan

Offline Spoons

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Re: Weighing DVI starter cultures
« Reply #4 on: April 08, 2014, 07:24:30 PM »
DCU is a measurement of how many viable bacteria are in the pack. It's potency does go down with time and environmental conditions such as humidity and temperature.

One great tip to preserve a culture (and it's otency) as long as possible is to divide the pack in 3 or 4 very small ziplock baggies. Identify each baggie with a number and only open the 1st baggie when using that culture. That way, the culture in the other 3 or 4 baggies don't suffer from a humidity exchange as often. Store all 3 or 4 baggies in a larger "sandwich sized" ziplock bag, so you don't mix up your cultures.
- Eric


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Offline ArnaudForestier

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Re: Weighing DVI starter cultures
« Reply #5 on: April 09, 2014, 08:37:34 AM »
Hey Bear, sorry, for some reason I'm not getting notifications of posts and PMs, so only happened on this.  Thanks for the cheese!  Spoons's info is great.  I'm pretty freakishly concerned with contamination so I try to transfer cultures as little as possible - most of mine will fit into some small ziplocks I got off e-bay, and then otherwise they go into a larger vacuum ziplock that can be vacuumed with a little handheld pump, pretty handy.  I mark the DCUs per gram where I have that info. 

Somewhere, can't recall where I read it, I saw the DCU thing is a measure of the ability of x amount of the lot culture to acidify y amount of milk by z degrees drop in pH, over a set quantity of time.  Which is as Spoons says, of course, a function of the viability of the cells.  Of course, knowing me, I might have just concocted that one up inside my own cranium.  ;D
- Paul

Offline Bear and Bunny cheese

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Re: Weighing DVI starter cultures
« Reply #6 on: April 09, 2014, 08:04:16 PM »
  Thanks for the advice JWalker, Arnaud and Spoons.  It's so refreshing to have such polite and easy going people to chat cheese with. 
  So is humidity the biggest enemy with culture exposure during handling?  I would expect simple exposure to air is a risk in itself?  I've used a glove box for doing sterile transfers of yeast cultures for brewing.  Could be good for this as well.  Are these powders as vulnerable as a yeast culture to contamination? I am pretty anal about sterility for culturing yeast and don't mind the trouble for cheese culture. 
  Arnaud, do you have a picture of your vacuum sealer?  I'm interested in getting it as well.
BnBC
 
Nathan

Offline Spoons

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Re: Weighing DVI starter cultures
« Reply #7 on: April 09, 2014, 08:27:40 PM »
It's so refreshing to have such polite and easy going people to chat cheese with. 

This forum is great, as long as we all agree that Beaufort is the best cheese. (We don't want to get Arnaud all riled up again)  :P

J'te taquine, Paul  ;D 
- Eric

Offline Bear and Bunny cheese

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Re: Weighing DVI starter cultures
« Reply #8 on: April 10, 2014, 02:06:31 PM »
  Well I guess I`m safe with Arnaud watching since, along with Gruyere and Emmenthal, Beaufort is the cheese I make most of.  BTW I used my cheese trier on one I made last July and I nearly jumped through the roof it was so good.  I`ll post some shots of it.  Just now eye formation.  And this is the main reason I`ve been so concerned about acidity as I have never been able to get eyes to form.  Reading the posts from Alpkase, Sailor, Linuxboy and of course Arnaud have been of extremely good use to me as I now know where to focus my energy, namely keeping salt levels low, proper pH and a good warm sit for the propionics to be happy. 
  I`ve been doing my B Linens wash before I put my wheels in the warmth as I`ve found I get less mould problems after a good two week long schmier-morge going.   It is also softer and more flexible in anticipation to the swelling (which of course has not happened yet unfortunately).
  My last Beaufort was scalded to 126F and pressed under whey for the first two flips and then pressed overnight in a cool area to slow down acidification.  I brined (saturated) for only six hours (flipping once) to keep the salt levels low.  This last one is still being B linens washed before going to the the warm room.  Hopefully it will finally have some eye formation as this is attempt number 5.  You folks have any other tips on alpine eye formation?   (Sorry maybe I should start this in another thread)
Nathan

Offline ArnaudForestier

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Re: Weighing DVI starter cultures
« Reply #9 on: April 11, 2014, 08:00:00 AM »
  Thanks for the advice JWalker, Arnaud and Spoons.  It's so refreshing to have such polite and easy going people to chat cheese with. 
  So is humidity the biggest enemy with culture exposure during handling?  I would expect simple exposure to air is a risk in itself?  I've used a glove box for doing sterile transfers of yeast cultures for brewing.  Could be good for this as well.  Are these powders as vulnerable as a yeast culture to contamination? I am pretty anal about sterility for culturing yeast and don't mind the trouble for cheese culture. 
  Arnaud, do you have a picture of your vacuum sealer?  I'm interested in getting it as well.
BnBC


Hey Bear, I'm with you on sterile technique - I'm more concerned with contamination than with humidity; the humidity issue I've tried to reduce by using little ziplock bags for the cultures themselves, which I squeeze down to the level of the culture, turn over and press lightly, then zip closed, which tends to leave a good seal without any visible air, anyway.  Then vacuum seal the larger pouch containing several small bags of culture. 

For the vacuuming system, I got the idea from Gianaclis Caldwell, in her book (Mastering Artisan Cheesemaking - great book, in my opinion, lot of fun to read). Here's the little unit and bags I use.  Works great, so far!

Quote from: Spoons
This forum is great, as long as we all agree that Beaufort is the best cheese. (We don't want to get Arnaud all riled up again)


Oh, great.  Now I've been found out.  And I was doing so well disguised as a mild-mannered, Wisconsin gypsy swing player 8)

- Paul


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